technical, economical and organizational analysis of informal brick

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technical, economical and organizational analysis of informal brick
UNIVERSIDAD AUTONOMA DE SAN LUIS POTOSI
F ACULTADES DE C IENCIAS Q UÍMICAS ,
I NGENIERÍA Y M EDICINA
P ROGRAMA M ULTIDISCIPLINARIO DE P OSGRADO
EN C IENCIAS A MBIENTALES
AND
C OLOGNE U NIVERSITY OF A PPLIED S CIENCES
I NSTITUTE FOR T ECHNOLOGY A ND R ESOURCES
M ANAGEMENT IN THE T ROPICS A ND S UBTROPICS
TECHNICAL, ECONOMICAL AND ORGANIZATIONAL ANALYSIS
OF INFORMAL BRICK PRODUCTION
IN TERCERA CHICA, SLP,MEXICO
THESIS TO OBTAIN THE DEGREE OF
MAESTRÍA EN CIENCIAS AMBIENTALES
DEGREE AWARDED BY UNIVERSIDAD AUTONOMA DE SAN LUIS POTOSI
AND
MASTER OF SCIENCE
TECHNOLOGY AND RESOURCES MANAGEMENT IN THE TROPICS AND SUBTROPICS
FOCUS AREA “ENVIRONMENTAL AND RESOURCES MANAGEMENT”
DEGREE AWARDED BY COLOGNE UNIVERSITY OF APPLIED SCIENCES
PRESENTS:
Swen Oliver Erbe
CO-DIRECTOR OF THESIS PMPCA:
PROF. DR. FERNANDO DÍAZ-BARRIGA
CO-DIRECTOR OF THESIS ITT:
PROF. DR. JOHANNES HAMHABER
ASSESSOR:
PROF. DR. MARCOS MONROY FERNÁNDEZ
SAN LUIS POTOSÍ, MÉXICO
FEBRUARY 2011
UNIVERSIDAD AUTONOMA DE SAN LUIS POTOSI
F ACULTADES DE C IENCIAS Q UÍMICAS ,
I NGENIERÍA Y M EDICINA
P ROGRAMA M ULTIDISCIPLINARIO DE P OSGRADO
EN C IENCIAS A MBIENTALES
AND
C OLOGNE U NIVERSITY OF A PPLIED S CIENCES
I NSTITUTE FOR T ECHNOLOGY A ND R ESOURCES
M ANAGEMENT IN THE T ROPICS A ND S UBTROPICS
TECHNICAL, ECONOMICAL AND ORGANIZATIONAL ANALYSIS
OF INFORMAL BRICK PRODUCTION
IN TERCERA CHICA, SLP, MEXICO
THESIS TO OBTAIN THE DEGREE OF
MAESTRÍA EN CIENCIAS AMBIENTALES
DEGREE AWARDED BY UNIVERSIDAD AUTONOMA DE SAN LUIS POTOSI
AND
MASTER OF SCIENCE
TECHNOLOGY AND RESOURCES MANAGEMENT IN THE TROPICS AND SUBTROPICS
FOCUS AREA “ENVIRONMENTAL AND RESOURCES MANAGEMENT”
DEGREE AWARDED BY COLOGNE UNIVERSITY OF APPLIED SCIENCES
PRESENTS:
SWEN OLIVER ERBE
PROF. DR. FERNANDO DÍAZ BARRIGA
PROF. DR. JOHANNES HAMHABER
PROF. DR. MARCOS MONROY FERNÁNDEZ
SAN LUIS POTOSÍ, MÉXICO
FEBRUARY 2011
STUDIES SUPPORTED BY
DEUTSCHER AKADEMISCHER AUSTAUSCH DIENST (DAAD)
CONSEJO NACIONAL DE CIENCIA Y TECNOLOGÍA (CONACYT)
LA MAESTRÍA EN CIENCIAS AMBIENTALES RECIBE APOYO A TRAVÉS DEL PROGRAMA
NACIONAL DE POSGRADOS (PNP -CONACYT)
Thesis Declaration
Erklärung / Declaración:
Name / Nombre: Swen Oliver Erbe
Matri.-Nr. / N° de matricula: 11067517 (CUAS), 0169620 (UASLP)
Aseguro que yo redacté la presente tesis de maestría independientemente y no use referencias ni
medios auxiliares a parte de los indicados. Todas las partes, que están referidas a escritos o a
textos publicados o no publicados son reconocidas como tales.
Ich versichere wahrheitsgemäß, dass ich die vorliegende Masterarbeit selbstständig verfasst
und keine anderen als die von mir angegebenen Quellen und Hilfsmittel benutzt habe. Alle
Stellen, die wörtlich oder sinngemäß aus veröffentlichten und nicht veröffentlichten Schriften
entnommen sind, sind als solche kenntlich gemacht.
Die Arbeit ist in gleicher oder ähnlicher Form noch nicht als Prüfungsarbeit eingereicht worden.
Hasta la fecha, un trabajo como éste o similar no ha sido entregado como trabajo de tesis.
San Luis Potosí, den /el ________________
Unterschrift / Firma: _______________
Estoy de acuerdo con una publicación posterior de mi tesis de maestría en forma completa o
parcial por las instituciones con la intención de exponerlos en el contexto del trabajo
investigación de las mismas.
Ich erkläre mich mit einer späteren Veröffentlichung meiner Masterarbeit sowohl auszugsweise,
als auch Gesamtwerk in der Institutsreihe oder zu Darstellungszwecken im Rahmen der
Öffentlichkeitsarbeit des Institutes einverstanden.
Acknowledgment
I dedicate this thesis to my deceased grandmother Magarete “Godi” Becker. I would like to thank my
family especially my two mothers Barbara Erbe and Christel Lauer for their unconditional love and
support.
My sincere gratitude goes to my supervisors: Dr. Fernando Díaz-Barriga for guiding me through my
studies and giving me suggestions and for his patience and believe in my work and Dr. Johannes
Hamhaber for his encouragement and support in preparing and accomplishing my thesis. I would also
like to thank my co-supervisor Dr. Marcos Monroy Fernández, for his kind support.
My gratitude goes as well to the staff of the two involved universities Universidad Autonoma San Luis
Potosi and University of Applied Science Cologne for making this international master happening. I
want to express special thanks to Simone Sandholz and Gabriela Cilia López for their administrative
and personal support.
Also I would want to thank the German Academic Exchange Service (DAAD), the Consejo Nacional de
Ciencia y Tecnología (CONACYT) and the Federal Ministry for Economic Cooperation and
Development for the financial supports during my studies in Mexico.
A special thanks go to Dr. Alba Corral of Universidad Autonoma Chihuahua for her time, guidance,
and willingness to share her knowledge.
Also many thanks to M.Sc. Luis Olvera Vargas, for his support and help to realize the maps of this
thesis.
Sincere thanks to the members of Grupo Ladrilleros y Artesanos la Tercera Chica A.C. for their time,
their patience, and support. It was an honor to meet with the brick producers who gave me an
insight into the brick production and their living conditions. Without their cooperation this
investigation would not have been possible.
Many thanks to my roommates Christine van Deuren and Isaac Jacob Chavez Acuña who became part
of my family.
Thanks to my second family Ufuk and Nurhayat Kücükinsel for always believing in me and always
reminding of who I am.
Special gratitude to my fellow compañeros of this master for becoming my good friends.
Finally, a warm acknowledgment to the following people for their friendship and support: Gely, David
(Waton), Patty, Pancho, Marisol, Mariana, Lupita, Magarita, Ruth, Johnny, Christian, Memo, Victor,
Marco, Nyzar, Cesar, Gaby, Simone, Karate, Tato, Marcos, Fido, Raul, Melissa, Tere, Noé.
Abstract
Small and medium-sized, traditional brick kilns are growing in cities of developing countries around
the globe supplying the urban population with cheap construction materials. The traditional brick
industry in Mexico, for example, depends on fuel-wasting equipment and technologies which
contribute to air pollution and emissions of greenhouse gases and therefore have a negative impact
on the socio - economic conditions of brick manufacturers and the ecology of cities. Cheap but also
particularly harmful fuels such as tires, plastics, wood, and used oil are the main fuels used for firing
the traditional brick kilns. In some cities of Mexico traditional kilns contribute significantly to air
pollution, and in almost every city they represent a serious health threat to the population of
marginalized neighborhoods, since in these settlements brick producers and their kilns are found.
The regulation of such firms by conventional means is impossible, since they are usually not
registered, numerous, geographically dispersed, highly competitive and not very profitable.
Mexico's medium-sized cities such as Puebla (1,399,519 inhabitants), Santiago de Queretaro
(1,097,028 inhabitants) and San Luis Potosi (685 934 inhabitants) now depend on the brick
production of hundreds of informal brick kilns, which are located in cities. Most of these brick kilns
were usually located in the periphery of cities, and are now often found due to rapid urban growth
within urban areas. One example is the district Tercera Chica in San Luis Potosi, which once formed
the periphery of the city, is now surrounded by new settlements integrating it and its approximately
120 brick kilns into the urban.
This thesis examines, using the district Tercera Chica as case study, the socio-economic
circumstances of the brick producers, and the organizational and technical conditions of the informal
brickyards in order to determine what kind of approaches could be useful to increase the efficiency
of the sector while reducing the negative environmental impact. The focus lies on strategies such as
relocation, promotion of cooperatives and cleaner production methods which are supported by the
United Nations in order to promote social, economic, and environmental sustainability in companies.
The socio-economic and organizational conditions of the brick producers and their families are of
particular attention. This is why in addition to surveys participatory methods such as participatory
workshops, SWOT-analysis, and observation methods were applied in order to actively involve the
brick producers in finding applicable solutions. In addition the brick kilns in Tercera Chica were
evaluated (inventory) on the basis of indicators such as kiln type and kiln condition.
Resumen
Numerosas ladrilleras tradicionales de pequeña y mediana escala están establecidas en las ciudades
crecientes de los países en desarrollo, donde abastecen a la población urbana con los materiales de
construcción baratos. La industria ladrillera tradicional en México por ejemplo, depende de
instalaciones y tecnologías que utilizan combustibles que contribuyen a la contaminación atmosférica
y las emisiones de gases de efecto invernadero y por lo tanto repercuten negativamente en el
aspecto socioeconómico de los ladrilleros y la ecología de las ciudades. Combustibles baratos pero
también perjudiciales tales como llantas, plásticos, madera usada y aceite usado son los principales
combustibles utilizados para la cocción de los ladrillos en los hornos tradicionales. En algunas
ciudades mexicanas, los hornos tradicionales contribuyen significativamente a la contaminación del
aire, y en casi todas las ciudades del país representan una grave amenaza sanitaria para la población
de los barrios pobres, ya que en estos asentamientos se encuentran las ladrilleras y los ladrilleros. La
regulación de estas empresas es imposible por los medios convencionales, ya que generalmente no
son registrados, son numerosos, dispersos geográficamente, altamente competitivos y sólo
marginalmente rentables.
En México ciudades medianas como Puebla (1.399.519 habitantes), Santiago de Querétaro
(1.097.028 habitantes) y San Luis Potosí (685 934 habitantes), dependen entretanto de la producción
de ladrillos de cientos de ladrilleras informales, que se encuentran en las ciudades. La mayoría de
estas ladrilleras se asientan generalmente en la periferia de las ciudades; no obstante, debido al
crecimiento acelerado de las ciudades, a menudo se encuentran dentro de ellas. Un ejemplo de ello
es el barrio Tercera Chica en San Luis Potosí, en este barrio actualmente existen alrededor de 120
hornos ladrilleros y en el pasado formó parte de la periferia de la ciudad; sin embargo, hoy en día
está rodeada de nuevos asentamientos humanos y se ha integrando al interior de la ciudad.
La presente investigación se enfoca en la colonia Tercera Chica de San Luis Potosí como caso de
estudio, analizando los aspectos socioeconómicos y las condiciones organizativas de los ladrilleros,
así como las características técnicas de los hornos que utilizan, con el fin de obtener aproximaciones
que sean útiles para realizar propuestas para el mejoramiento de la eficiencia de dicho sector y al
mismo tiempo reducir el impacto ambiental negativo. Las actividades se concentran en estrategias
como la reubicación, la promoción de las cooperativas y los métodos de producción más limpios que
están promocionados por las Naciones Unidas, con el fin de alentar a las empresas hacia la
sustentabilidad social, económica y ambiental. Las condiciones socioeconómicas y organizativas de
los ladrilleros y sus familias son de interés especial, por lo que además de las encuestas de
formularios, se aplicaron métodos participativos tales como talleres participativos, el análisis FODA y
métodos de observación para integrar activamente a los ladrilleros en la búsqueda de soluciones
viables. Además, se evaluaron los hornos (inventario) mediante indicadores como localización
geográfica, forma, tipo y condiciones actuales de los mismos.
Zusammenfassung
Dutzende von klein- und mittelständische, traditionellen Ziegelsteinöfen sind in wachsenden Städten
der Entwicklungsländer angesiedelt, welche die Stadtbevölkerung mit billigen Baumaterialien
versorgen. Die traditionelle Ziegelei-Industrie, in Mexiko zum Beispiel, ist abhängig von
brennstoffverschwenderischen Anlagen und Techniken, welche zur Luftverschmutzung und
Emissionen von Treibhausgasen beitragen und sich folglich negative auf die Sozioökonomie der
Ziegelsteinproduzenten und Ökologie der Städte auswirken. Günstige aber auch besonders
schädliche Brennstoffe wie Reifen, Kunststoffe, Altholz und gebrauchtes Öl sind die Hauptbrennstoffe
die zur Feuerung der traditionellen Ziegelsteinöfen genutzt werden. In einigen Städten Mexikos
tragen die traditionellen Öfen maßgeblich zur Luftverschmutzung bei und in praktisch jeder Stadt
stellen sie eine ernste Gesundheitsgefahr für die Bevölkerung der verarmten Nachbarschaften dar,
da innerhalb dieser Siedlungen die Ziegeleien, sowie Ziegelbrenner vorzufinden sind. Die Regulierung
solcher Firmen durch herkömmliche Mittel ist praktisch unmöglich, da sie meist nicht registriert,
zahlreich, geografisch verteilten, auf hohen Wettbewerb beruhend, und nur minimal profitabel sind.
Mexikos mittelgroße Städte wie Puebla (1.399.519 Bewohner), Santiago de Queretaro (1.097.028
Bewohner) und San Luis Potosi (685.934 Bewohner) hängen mittlerweile von der Ziegelproduktion
von hunderten von informellen Ziegeleien, die sich in den Städten befinden, ab. Die meisten dieser
Ziegeleien wurden üblicherweise in der Peripherie der Städte angesiedelt, und sind inzwischen durch
das rapide Stadtwachstum oftmals innerhalb der Stadt vorzufinden. Ein Beispiel hierfür ist der Bezirk
Tercera Chica in San Luis Potosi, der einst die Peripherie der Stadt bildete, und heute von neuen
Siedlungen umgeben ist. Es befinden schätzungsweise 120 Ziegeleien in diesem Bezirk von San Luis
Potosi.
Die vorliegende Studie untersucht am Fallbeispiel Tercera Chica, San Luis Potosi die
sozioökonomischen Umstände der Ziegelproduzenten, sowie die organisatorischen und technischen
Gegebenheiten der Ziegeleien. So soll erforscht werden welche Ansätze sinnvoll wären, um die
Effizienz des Sektors zu steigern und gleichzeitig die negativen Umwelteinflüsse zu senken.
Schwerpunkte hierbei sind Strategien wie Umsiedlung, Förderungen von Kooperativen und Cleaner
Production Methoden, welche von den Vereinten Nationen gefördert werden, um in Unternehmen
die soziale, ökonomische und ökologische Nachhaltigkeit zu begünstigen. Die sozioökonomischen
und organisatorischen Verhältnisse der Ziegelproduzenten und ihrer Familien sind hierbei von
besonderem Augenmerk, weshalb neben Fragebögen auch partizipative Methoden wie Workshops,
SWOT-Analysen, und die Dokumentation vom Produktionsprozess angewendet wurden, um die
Ziegelproduzenten aktiv in anwendbare Lösungsfindungen einzubinden. Zudem wurden die
einzelnen Ziegelsteinöfen anhand von Indikatoren, wie Konstruktionsweise und –zustand evaluiert
(Bestandsaufnahme).
Table of Content
List of Figures........................................................................................................................................... V
List of Tables .......................................................................................................................................... VII
List of Abbreviation ................................................................................................................................ IX
1.
2.
Introduction ..................................................................................................................................... 1
1.1.
Problem Statement ................................................................................................................. 3
1.2.
Justification.............................................................................................................................. 4
1.3.
Hypothesis ............................................................................................................................... 4
1.4.
General objective .................................................................................................................... 4
1.5.
Specific objectives ................................................................................................................... 4
Conceptual Framework ................................................................................................................... 6
2.1.
Environmental impacts of traditional brick production .......................................................... 6
2.1.1.
Fuels (Wood, Coal, Gas, Tires, Plastics, Used oil, and Garbage)...................................... 6
2.1.2.
Impacts on air, soil and biodiversity, water, human ....................................................... 9
2.2.
Socio-economic review of traditional brick making industry ................................................ 12
2.2.1.
Socio-economic conditions of traditional brick making industry in developing countries
12
2.2.2.
2.3.
Alternatives for traditional brick making industry ................................................................ 16
2.3.1.
3.
Child Labor ..................................................................................................................... 14
Cleaner Production (CP) and traditional brick making .................................................. 16
2.3.1.1.
Good housekeeping ............................................................................................... 18
2.3.1.2.
Product modification ............................................................................................. 19
2.3.1.3.
Input substitution .................................................................................................. 20
2.3.1.4.
Technology modification ....................................................................................... 21
2.3.2.
Relocation of traditional brick kilns ............................................................................... 26
2.3.3.
Organized traditional brick maker ................................................................................. 29
Methodology ................................................................................................................................. 32
3.1.
Data collection ....................................................................................................................... 32
I
4.
3.1.1.
Secondary sources ......................................................................................................... 32
3.1.2.
Primary sources ............................................................................................................. 32

About product modification .............................................................................................. 34

About mechanization and new kiln design ....................................................................... 35
3.2.
Analysis of information ......................................................................................................... 36
3.3.
Review of methodology......................................................................................................... 38
3.3.1.
Observation ................................................................................................................... 38
3.3.2.
Participatory Action Research (PAR) ............................................................................. 39
3.3.3.
SWOT analysis ............................................................................................................... 41
Study Area ..................................................................................................................................... 43
4.1.
Geographical space ............................................................................................................... 43
4.1.1.
Location ......................................................................................................................... 43
4.1.2.
Climate........................................................................................................................... 43
4.1.3.
Geology and edaphology ............................................................................................... 44
4.1.4.
Soil ................................................................................................................................. 44
4.1.5.
Hydrology ...................................................................................................................... 44
4.1.6.
Vegetation ..................................................................................................................... 45
4.1.7.
Urban structure (segregation, transport, etc.) .............................................................. 45
4.2.
Cultural space ........................................................................................................................ 46
4.2.1.
Population ..................................................................................................................... 46
4.2.2.
Education ....................................................................................................................... 47
4.2.3.
Dwellings ....................................................................................................................... 48
4.2.4.
Economy ........................................................................................................................ 49
4.3.
Mechanisms to protect the environment in Mexico............................................................. 51
4.3.1.
5.
Environmental policies for traditional brick industry in Mexico ................................... 52
Results and analysis ....................................................................................................................... 53
5.1.
Results of surveys of brick producers in Tercera Chica, SLP.................................................. 53
5.1.1.
Results of socio-economical conditions of brick producers in Tercera Chica ............... 53
II
5.1.1.1.
Methodology ......................................................................................................... 53
5.1.1.2.
Results of socio-economical survey of brick producers in Tercera Chica.............. 53
5.1.1.3.
Conclusion ............................................................................................................. 57
5.1.2.
Results of survey about brick industry in Tercera Chica ............................................... 59
5.1.2.1.
Methodology ......................................................................................................... 59
5.1.2.2.
Kiln industry in Tercera Chica ................................................................................ 59
5.1.2.3.
Fuels....................................................................................................................... 60
5.1.2.4.
Brick production .................................................................................................... 61
5.1.2.5.
Labor conditions of brick workers ......................................................................... 62
5.1.3.
Production costs of bricks ............................................................................................. 64
5.1.3.1.
Fuels....................................................................................................................... 64
5.1.3.2.
Raw brick material ................................................................................................. 64
5.1.3.3.
Workforce .............................................................................................................. 64
5.1.4.
Cooperative ................................................................................................................... 65
5.1.5.
Relocation ...................................................................................................................... 65
5.1.6.
Governmental support .................................................................................................. 66
5.1.7.
Implemented improvements by brick producers .......................................................... 66
5.1.8.
Conclusion ..................................................................................................................... 67
5.2.
Kiln locations and conditions of Grupo Ladrilleros y Artesanos la Tercera Chica A.C. .......... 68
5.2.1.
Methodology ................................................................................................................. 68
5.2.2.
Results of kiln location and conditions .......................................................................... 68
5.2.3.
Selling points of bricks ................................................................................................... 72
5.2.4.
Conclusion ..................................................................................................................... 73
5.3.
Non-participative observation .............................................................................................. 74
5.3.1.
Methodology ................................................................................................................. 74
5.3.2.
Brick production processes ........................................................................................... 74
5.3.3.
Observation of child labor ............................................................................................. 83
5.3.4.
Conclusion ..................................................................................................................... 83
5.4.
Participative workshops in Tercera Chica with the traditional brick makers ........................ 85
5.4.1.
Methodology ................................................................................................................. 85
III
5.4.2.
5.4.2.1.
Good housekeeping ............................................................................................... 85
5.4.2.2.
Product modification ............................................................................................. 86
5.4.2.3.
Input substitutions (fuels) ..................................................................................... 87
5.4.2.4.
Mechanization and new brick kiln design ............................................................. 87
5.4.2.5.
Relocation .............................................................................................................. 88
5.4.2.6.
Cooperatives .......................................................................................................... 89
5.4.3.
6.
Results of the first workshop......................................................................................... 85
Second participatory workshop: SWOT analysis ........................................................... 90
5.4.3.1.
Methodology ......................................................................................................... 90
5.4.3.2.
Results of the second workshop ........................................................................... 90
5.4.3.3.
Conclusion ............................................................................................................. 95
Conclusions and recommendations .............................................................................................. 97
6.1.
Recommendation for further studies .................................................................................... 99
References ........................................................................................................................................... 100
Appendix 1: Kiln comparison ............................................................................................................... 108
Appendix 2: Official Mexican Standards for air quality measurement and emission content evaluation
............................................................................................................................................................. 119
Appendix 3: Questionnaire.................................................................................................................. 120
Appendix 4: Results of production costs and income ......................................................................... 125
Appendix 5: Brick kiln location (GPS), conditions and photos ............................................................ 130
Appendix 6: Roofing design for drying area of raw bricks .................................................................. 141
Appendix 7: Metering pump ............................................................................................................... 143
IV
List of Figures
Figure 2.2.1: Distribution of child labor according to sector and sex, 2007 ......................................... 15
Figure 2.3.1: A basic brick clamp ........................................................................................................... 23
Figure 2.3.2: Insulation of a fired scove clamp/kiln .............................................................................. 24
Figure 3.3.1: Traditional SWOT analysis ................................................................................................ 42
Figure 4.1.1: Map of Mexico, map of San Luis Potosi and map of Tercera Chica ................................. 43
Figure 4.1.2: Climate diagram of San Luis Potosi .................................................................................. 44
Figure 4.2.1: Total population and gender distribution in Tercera Chica ............................................. 46
Figure 4.2.2: Population and age group in Tercera Chica ..................................................................... 46
Figure 4.2.3: Health service of the population in Tercera Chica ........................................................... 47
Figure 4.2.4: Educational level of population of the age 15 years older in Tercera Chica .................... 47
Figure 4.2.5: Construction materials of private dwelling in Tercera Chica ........................................... 48
Figure 4.2.6: Infrastructure and public services of the private dwellings in Tercera Chica .................. 48
Figure 4.2.7: Dwelling ownership in Tercera Chica ............................................................................... 49
Figure 4.2.8: Population of age 12 and older economically inactive in Tercera Chica.......................... 49
Figure 4.2.9: Labor agreement of the employed population in Tercera Chica ..................................... 50
Figure 5.1.1: Interviewed brick producers in Tercera Chica: Age groups ............................................. 54
Figure 5.1.2: Educational level of brick producers in Tercera Chica ..................................................... 54
Figure 5.1.3: Dwelling and household of brick producer families in Tercera Chica .............................. 55
Figure 5.1.4: Access of the brick producers’ dwellings to public services in Tercera Chica .................. 56
Figure 5.1.5: Means of transportation used by brick producers in Tercera Chica ................................ 56
Figure 5.1.6: Used fuels for firing process among participants of the survey ...................................... 60
Figure 5.1.7: Minimum, average and maximum number of brick production per kiln and firing in
Tercera Chica ......................................................................................................................................... 61
Figure 5.1.8: Average number of bricks produced per month in Tercera Chica and average rainfalls
per month in San Luis Potosi ................................................................................................................. 62
Figure 5.1.9: Participants working hours per day in the brick production of Tercera Chica ................. 63
Figure 5.1.10: Type of employment among participants, Tercera Chica .............................................. 63
V
Figure 5.1.11: Average expenditure (Mexican pesos) per raw brick material per brick production in
Tercera Chica ......................................................................................................................................... 64
Figure 5.2.1: Relation of wind direction to firing chamber ................................................................... 69
Figure 5.2.2: Map of locations of kilns owned by members of Grupo Ladrilleros y Artesanos la Tercera
Chica A.C. in residential area of SLP ...................................................................................................... 70
Figure 5.2.3: Map of locations of kilns owned by members of Grupo Ladrilleros y Artesanos la Tercera
Chica A.C. and location of selling points of bricks ................................................................................. 71
Figure 5.3.1: Panorama photos of a brick making area ........................................................................ 74
Figure 5.3.2: Process step of mixing the soil, water, and additives ...................................................... 77
Figure 5.3.3: Process step molding the bricks ....................................................................................... 78
Figure 5.3.4: Process step of drying the molded bricks ........................................................................ 79
Figure 5.3.5: Scotch kiln (traditional kiln) in Tercera Chica ................................................................... 80
Figure 5.3.6: Process step of loading the kiln with molded bricks ........................................................ 80
Figure 5.3.7: Process step of firing the kiln ........................................................................................... 81
Figure 5.3.8: Process step of classifying burnt bricks ............................................................................ 83
VI
List of Tables
Table 2.1.1: Emissions by fuels ................................................................................................................ 7
Table 2.2.1: Number of brick kilns and organized brick producers: Ciudad Juarez, Saltillo, Torreon and
Durango ................................................................................................................................................. 13
Table 2.2.2: Child labor of high risks identified by IPEC per country .................................................... 14
Table 2.3.1: Solutions to increase efficiency and reduce waste in brick production ............................ 17
Table 2.3.2: CP – Method: Good housekeeping .................................................................................... 18
Table 2.3.3: CP – Method: Product modification .................................................................................. 19
Table 2.3.4: CO2 emitted by burning of bricks (m2) Traditional kiln using wood and sawdust (Cusco) 19
Table 2.3.5: CP – Method: Input substitution ....................................................................................... 20
Table 2.3.6: Typical biomass fuels net calorific values .......................................................................... 21
Table 2.3.7: CP – Method: Technology modification ............................................................................ 22
Table 2.3.8: Disadvantages of brick clamps .......................................................................................... 22
Table 2.3.9: Advantages of brick clamps ............................................................................................... 23
Table 2.3.10: Energy use and efficiency by kiln and fuel types ............................................................. 25
Table 2.3.11: Example for Ciudad Juarez: Categorized indicators for the analysis of possible relocation
areas for the traditional brick making industry ..................................................................................... 28
Table 2.3.12: Benefits of relocation ...................................................................................................... 29
Table 2.3.13: Some benefits of an association/cooperative ................................................................. 30
Table 3.1.1: Participative workshop topics: Ten actions of good housekeeping .................................. 34
Table 3.1.2: SWOT Matrix used for participative workshop ................................................................. 36
Table 3.2.1: Indicators to evaluate conditions of kilns in Tercera Chia................................................. 36
Table 3.3.1: Observation methods ........................................................................................................ 39
Table 3.3.2: Strengths and weaknesses of observational methods ...................................................... 39
Table 3.3.3: Characteristics of PAR ........................................................................................................ 40
Table 3.3.4: Some strengths and weaknesses of participatory action research ................................... 41
Table 3.3.5: Common methods used in PAR ......................................................................................... 41
Table 4.1.1: Average monthly temperature and precipitation in ......................................................... 44
VII
Table 4.3.1: Implemented policies of four Mexican state governments regulating air pollution of
informal brick industry. ......................................................................................................................... 52
Table 5.1.1: Comparison kiln age with duration of firing process......................................................... 60
Table 5.1.2: Amounts of fuels used per firing among participants of the survey ................................. 61
Table 5.1.3: Average price per brick (MXN) .......................................................................................... 61
Table 5.1.4: Average price per fuel ....................................................................................................... 64
Table 5.2.1: Evaluation of brick kiln conditions in Tercera Chica .......................................................... 68
Table 5.3.1: Production process and impacts of traditional brick industry in Tercera Chica, SLP,
Mexico ................................................................................................................................................... 76
Table 5.4.1: The experience of good housekeeping methods of the traditional brick makers in Tercera
Chica ...................................................................................................................................................... 85
Table 5.4.2: SWOT: Vertical Shaft Brick Kiln .......................................................................................... 91
Table 5.4.3: SWOT: Good practices ....................................................................................................... 91
Table 5.4.4. SWOT: Mechanization (Dosificadora) ................................................................................ 92
Table 5.4.5: SWOT: Biomass as fuel ...................................................................................................... 92
Table 5.4.6. SWOT: Cooperative ........................................................................................................... 93
Table 5.4.7: SWOT: Relocation .............................................................................................................. 94
Table 5.4.8: SWOT: Market situation .................................................................................................... 94
VIII
List of Abbreviation
CDM
Clean Development Mechanism
CENICA
Centro Nacional de Investigación y Capacitación Ambiental (National
Environmental Research and Training Center)
CER
Certified Emission Reduction
CONASAMI
Comisión Nacional de los Salarios Mínimos (National Commission on Minimum
Wages)
CP
Cleaner Production
FEMAP
Mexican Federation of Private Associations
FOCER
Energia Renovable para America Central (Renewable Energy for Central
America)
GTZ
German Society for Technical Cooperation
HP
Horse Power
INEGI
Instituto Nacional de Estadística y Geografía (National Institute of Statistics and
Geography)
IPEC
International Programm on the Elimination of Child Labour
MK2
Marquez Kiln (type of ecological kiln)
MXN
Mexican Peso (ISO 4217; formerly MXP)
PAN
Partido Acción Nacional (National Action Party)
PAR
Practipatory Action Research
PRAL
Programa Regional de Aire Limpio (Regional Program for Clean Air)
PRI
Partido Revolucionario Institucional (Institutional Revolutionary Party)
SEMARNAT
Secretaría de Medio Ambiente y Recursos Naturales (Ministry of Environment
and Natural Resources)
SLP
San Luis Potosi
SWOT - Analysis
Strength – Weakness – Opportunity – Threats – Analysis
UASLP
Universidad Autonoma de San Luis Potosi
(Autonomous University of San Luis Potosi)
UNEP
United Nations Environment Programme
UNFCCC
United Nations Framework Convention on Climate Change
IX
USD
U.S. Dollar
VAT
Value Added Tax
VSBK
Vertical Shaft Brick Kiln
X
1.
Introduction
Population and economy growth in cities of developing countries1 around the world lead to more
construction sites and therefore a higher demand of cheap construction materials. Traditionally
produced bricks feed this urge at a high prize. They are mainly fired with a variety of cheap, highlypolluting fuels such as plastic refuse, old tires, used oil, wood, and all kinds of residential and
industrial waste materials causing toxic air and soil pollution. Effected most are residents of the
traditional respectively informal brick producing communities which are usually the poorest
neighborhoods; and of course brick producers and their workers themselves (Blackman, Shih and
Newbold, 2000). Due to rising numbers of kilns, emissions from informal brick production are held
responsible for great parts of air pollution. In some cities only peaked by the emissions of the
vehicular fleet (Romo Aguilar et al., 2004).
In Mexico, as in developing countries around the world, small-scale traditional brick kilns are a
notorious informal sector source of urban air pollution. According to estimations in 1994 there have
been approximately 20,000 traditional brick kilns in Mexico (Johnson et al. quoted in Blackman,
2000) where many large cities support several hundred.
The air pollution caused by the traditional brick industry of Mexican border cities became of
governmental concern due to the fact that air pollution in El Paso/Ciudad Juarez is a primary cause of
regional environmental degradation and affected US-urbanizations situated on the Mexican border
(Liverman, 1999). Efforts to reduce air pollution from the Ciudad Juarez brick kilns initially began in
the early 1990s. Three groups have been researching methods of constructing brick kilns to make
them more efficient by improving the combustion process and reducing fuel requirements (TCEQ,
2002).
Efforts to reduce or control pollution from traditional kilns in Mexico have not been coordinated at
the national level. Rather, individual municipalities have implemented a variety of strategies which
have had decidedly mixed success (Blackman, 2000). The implemented strategies include: Cleaner
Technological Change (good housekeeping, kiln design and energy efficiency just to name some), fuel
substitution and efficiency, relocation, green subsidies, policies and education initiatives among
others. However, the experience shows that the social and economic context of people working in
this industry does not allow important changes, therefore making any initiative for brick kiln
improvements and/or their relocation difficult (Romo Aguilar et al., 2004).
1
A first strategy to make construction more sustainable is promoting low-energy or renewable materials, such
a as earth, bamboo or plantation grown timber. On the other hand the brick production industry has been
supported because it generates millions of jobs and traditional small-scale brick making industries provide
bricks to growing population in cities to a price which can be afforded as well by the people living in slums
(Schilderman & Mason, 2009).
1
The present investigation focuses on the traditional brick industry in the city of San Luis Potosi (SLP),
Mexico and studies possible strategies for these traditional brick makers (Spanish: ladrilleros) in
order to lessen the environmental impact that the traditional brick making industry has. Strategies
which have already been applied in other cities such as cleaner technologies (good housekeeping,
product modification, input substitution, and technology modification), relocation and organizational
forms of brick producers (associations) will be examined, considering the socio-economic conditions
of Tercera Chica, and will be evaluated in a participative process together with the brick producers.
The industrial city San Luis Potosi, the capital of the state of the same name is located in central
Mexico and has a population of 690,481 in the city (approximately 1,021,688 in the metropolitan
area) (INEGI, 2005). The traditional brick industry is distributed mainly in three areas, two are located
in the periphery of the city, and one area is situated in the urban area close to the old center. The
focus of the present study is the traditional brick industry placed in the district Tercera Chica which is
located within city limits. It has attracted attention because it is supposed to be a health hazard to
those who live nearby.
This investigation on traditional brick manufacturing at small scale industry level in Tercera Chica, San
Luis Potosi aims to make recommendations of feasible technologies and organizational opportunities
(relocation and CDMs) considering the socio-economical context of the traditional brick producers in
Tercera Chica. The district Tercera Chica is home to approximately 120 small-scale brick kilns, which
use fuels such as used tires, plastic, scraped wood, used motor oil, and refuse.
In the second chapter the study presents first a review of the environmental impacts that traditional
brick making has, socio-economic conditions of traditional brick producers in developing countries
reviewing additionally the informal brick industries in Mexico (income, process, employees etc.); and
cleaner technologies among other strategies which were implemented in developing countries
around the world to improve the socio-economic and environmental circumstances of traditional
brick industries.
The third chapter consists of the methodology describing the chosen methods for data collection,
data analysis, and review of advantages and disadvantages of applied methods.
The forth chapter outlines the study area’s geographical space and cultural space, and the
environmental regulations of Mexico.
The fifth chapter identifies the socio-economic conditions and problems in the district Tercera Chica
carrying out a survey applied with the brick producers of Tercera Chica. In addition it evaluates the
manufacturing brick process using a survey and participative observation. The described strategies
(clean technology, green bricks, etc.) are evaluated in a participative workshop together with the
brick producers using the SWOT method.
2
The sixth chapter resumes recommendations and identifies possible methods elaborated by findings
of the socio-economic conditions, manufacturing process and cleaner technologies and presents
technologies and strategies which are non-applicable because of the socio-economical context.
1.1.
Problem Statement
Environmental issues: According to different scientific researches informal firms are usually more
pollution-intensive than large firms in the same industry because they lack pollution control
equipment and access to basic sanitation services (Lanjouw, 1997; Blackman, 2006:53-59). Since the
traditional respectively informal brick industry is a significant source of employment and is often
situated in poor residential areas its emissions directly affect a considerable population2.
Traditional kiln emissions represent an urgent environmental problem as soil, air and, water is
contaminated because brick kilns are primarily associated with carbon monoxide and particulate
emissions, depending on the fuels used, they also emit volatile organic compounds, nitrogen oxide,
sulfur dioxide, heavy metals, and carbon dioxide, the most important greenhouse gas (Johnson et al.,
1994).
In addition to contributing to city-wide pollution, traditional kilns are a serious local health hazard to
those living in areas near the kilns. In many cases brick producers first settle in colonies situated on
the outskirts of the city. Over time, however, most have been enveloped by urban sprawl (examples
Ciudad Juarez, Zacatecas, San Luis Potosi etc.).
Although the principal factor of contamination in urban areas is the traffic, it can be assumed that
given the sheer number of such firms in developing countries, the aggregated environmental impacts
can be very significant. Estimations show that the Asian informal brick production alone emits 180
million tons of CO2 annually which resembles one third of the CO2 emissions caused by the global
aviation industry (550 million tons/year) in 2008 (Heierli and Maithel, 2008).
Socio-economic issues:
The cost-efficiency of traditional brick industries is low, even though the distribution of traditionally
made bricks is high. Furthermore the traditional brick industry is vulnerable to changes in prices of
the primary materials (water, soil, sawdust and wood), which can lead to the insolvency of a
traditional brick industry in a city. The families of brick producers live in marginalized neighborhoods,
often without basic services (FEMAP quoted in Blackman & Bannister 1998). As well child labor is a
common phenomenon in manufacturing brick industries (Varillas, 2003).
2
Most of the residential areas or slums where poor people live have a higher population density than middle class or
wealthier residential areas.
3
The traditional brick industry is a labor intensive, low technology activity in which generates low
incomes for the brick-producers. Most of the brick producers have an income which allows them to
pay just for basic necessaries. The traditional brick making as any informal industry is highly
competitive (since barriers to entry are relatively low) and therefore brick producers are under
considerable pressure to cut costs regardless of the environmental impact or minimum wages for
their employees.
1.2.
Justification
The traditional brick industry in Tercera Chica is located within city limits, which causes
environmental impacts on the neighborhood and probably the city itself. Studies about the health of
children are in process by doctoral students of the Universidad Autonoma de San Luis Potosi.
Another step to approach the problem of contamination caused by the brick producers is to develop
technical, spatial respectively organizational strategies together with the brick producers to reduce
the pollution of traditional brick kilns, in a participative process considering the socio-economic
conditions of the participants (brick producers). The brick producers are interested in implementing
changes due to following reasons: they are aware of causing contamination, market situation (low
demand; high competition) and because of pressure from the state government.
1.3.
Hypothesis
The research of technical, social-economic, and organizational conditions of informal brick making
helps to identify technologies, indicators with socio-economic objectives, and to formulate
appropriate interactions (spatial, organizational structures) for the promotion of cleaner
technologies which can lessen the environmental pollution.
1.4.
General objective
Investigation of the technical, socio-economical and organizational conditions of the informal brick
making industry in the district Tercera Chica, SLP in order to find appropriate interactions to minimize
the environmental contamination and improve the socio-economical impacts.
1.5.

Specific objectives
Investigating number of traditional brick kilns in Tercera Chica, SLP and their capacities and
conditions.

Socio-economic evaluation of the informal brick producers and analysis of possibilities to
improve economic conditions.
4

Estimation of environmental impacts caused by traditional brick making technologies.
Analyze existing data of pollution caused by traditional brick industry related to fuels being
used in order to estimate possible environmental impacts.

Evaluation of possible strategies of cleaner technology, spatial and organizational
alternatives considering the socio-economic context of brick producers.
5
2.
Conceptual Framework
The conceptual framework is structured in three different parts: the environmental impacts which
are caused by the traditional brick industry, the socio-economic conditions of the traditional brick
making industry in developing countries, and alternatives for the traditional brick making industry.
2.1.
Environmental impacts of traditional brick production
Traditional brick production has different impacts on the environment and human health. Brick
producers use waste materials like sawdust, wood shavings, and scrap wood as fuels which contain
resins and chemical compounds (Huston et al., 2002). Also cheaper waste materials such as old tires,
used motor oil, plastics, and garbage (Huston et al., 2002).
Beside this, traditional kilns have an inefficient energy use, because heat is not well distributed inside
the kiln and lost due to bad insulation of the kiln walls which generates higher fuel consumptions,
more firing time, and more emissions (The Cadmus Group Inc., 2009).
Mexican laws and federal agencies such as Procuraduría Federal de Protección al Ambiente
(PROFEPA) consider it illegal to use materials like tires, plastics, garbage and motor oil as fuel for
brick firing (Huston et al., 2002), but most of the brick producers live in poverty and their socioeconomical situation does not allow them to acquire less polluting fuels which are usually more
costly (Romo Aguilar et al., 2004).
Around the world different kinds of materials are being used to fire brick kilns. There are also many
different kinds of kilns operating, some are better in terms of energy efficiency and produce less
polluting emissions. But the majority of kilns used in traditional brick making produces huge
quantities of contaminants which are incorporate into the air and from there to other abiotic (soil
and water) and biotic elements (animals, plants, humans).
2.1.1. Fuels (Wood, Coal, Gas, Tires, Plastics, Used oil, and Garbage)
Informal brick producers decide which kind of fuel or fuels are going to be used by two factors; costs
and availability.
Each fuel causes pollution (Table 2.1.1), but some are worse than others. These are some of the most
commonly used fuels in informal brick production and their most important pollutants.
6
Table 2.1.1: Emissions by fuels
Fuels
Emissions
Wood
Oil impregnated wood/ wood
shavings
Mesquite and Tecate
NOX, VOC, CO, PM10 and PM2.5, SO2
Sawdust
Saladillo or typical flora of the
region, cob corn, coffee husks,
coconut shell
Used Oil
NOX, VOC, CO, PM10 and PM2.5, NH3
LP Gas
CO2, CO, PM, SO2, CH4, N2O, NOX, TOC, CH4
Tires
Cow manure, chicken manure, or
manure
Waste and plastics
CO2, CO, Metals, NOX, VOC, CO, PM10 and PM2.5, SO2
Oil
NOX, VOC, CO, PM10 and PM2.5, SO2, NH3
NOX, VOC, CO, PM10 and PM2.5, NH3
NOX, VOC, CO, PM10 and PM2.5, NH3
CO2, CO, NOX, PM10, SO2, TOC, HCl, Cr, Ni, CH4
COT, Dioxins and furans, CH4, NH3
CH4, CO2, N2O, Dioxins and furans, TOC, VOC
CO2, CO, NOX, CO, PM10 and PM2.5, SO2, CPM-COT, CPM-IOR, CPM-ORG,
CH4, Particles, N2O, Polycyclic Organic Matter (POM) and formaldehyde
(HCOH), Chlorides, Fluorides, Ni, V, CO, Cry Pb
Hazardous Waste solid tow, waste
TOC, VOC
from filtration
Sole and Leather
CO2, CO, NOX, VOC, PM10 and PM2.5, SO2, Hexavalent chromium, Metals
Source: IPCC, EPA, INEM quoted by Trejo Cuevas, 2010

Wood and Coal
Wood used as fuel is responsible for the emissions of both trace and non-trace greenhouse gases,
such as CO2 (carbon dioxide), CH4 (methane), CO (carbon monoxide), N2O (nitrous oxide), NOX (mononitrogen oxides) and NO (nitrogen oxide). According to Alam (2006) it is important to know the
accurate estimation of greenhouse gas emission from biomass fuel burning in small combustion and
their significance in order to suggest suitable mitigation options (WB, 1998; ITDG, 2005 quoted by
Alam, 2006: 33). Depending on the source (or process) of the fuel, volatile organic compounds (VOC)
and hazardous air pollutants including PAH, dioxins and furans can be emitted which are extremely
potent and toxic (Beauchemin & Tampier, 2008).

Gas
Liquefied Petroleum Gases (LPG or LP gases) include propane, propylene, butane, and butylenes;
propane is the most common gas used in kilns as well as in other industrial and domestic activities.
LPG gas is considered a clean fuel; however, “gaseous pollutants such as nitrogen oxides (NOX),
carbon monoxide (CO), and organic compounds are produced as are small amounts of sulfur dioxide
(SO2) and particular matter (PM)” (EPA, 2008: 2) mainly due to poor burner designs which can cause
improper combustions.
7
The greenhouse gases emitted by propane and other gas combustions are carbon dioxide (CO 2),
methane (CH4) and nitrous oxide (N2O); but the emission amount of each gas can be reduced by the
control of different factors such as combustion temperature, etc.

Tires
Tires used as fuel for kilns are one of the most pollutant sources; according to Lane (2007), the list of
contaminants include: nitrogen oxides (NOX), particulate matter (PM), sulfur dioxide (SO2), dioxin and
furans, carbon monoxide (CO) and carbon dioxide (CO2), polycyclic aromatic hydrocarbons (PAHs)
and unburned hydrocarbons, volatile organic compounds (VOCs), heavy metals such as zinc oxide,
lead, arsenic, chromium and mercury, also nickel, cadmium, formaldehyde, acetaldehyde, and others
which are associated with incomplete combustion and tires´ chemical composition (Mesaros, 2007).

Plastics
Plastics are common components of garbage used as fuel in informal brick kilns; and the most
dangerous emissions can be caused by plastics containing organochlor-based substances like
polyvinyl chloride (PVC) because harmful quantities of dioxins are emitted to the atmosphere
(Belliveau, 2003; WECF, 2008).
Other pollutants which are released from burning plastic waste are mercury, polychlorinated
biphenyls (PCBs)3, dioxins, and furans. All of which persist for long periods of time in the environment
and have a tendency to bio-accumulate in organisms of the food chain (WECF, 2008).

Used oil
Emissions from burning used or waste oils reflect the compositional variations of them; potential
pollutants like carbon monoxide (CO), sulfur oxides (SOx), nitrogen oxides (NOX), particulate matter
(PM), particles less than 10 micrometers in size (PM10), toxic metals, organic compounds (Benzene,
toluene, polychlorinated biphenyls, polychlorinated, and others hazardous compounds), hydrogen
chloride and greenhouse gases like carbon dioxide (CO2) and methane (CH4) are included in used oil
burning emissions (EPA, 1996).
3
PCB levels in the environment have dropped since the manufacturing and use of the compounds were
curtailed (in USA 1979), but high quantities of electrical equipment, plastics (e.g. PVC), adhesives, paper, inks,
paints and dyes manufactured before the ban are still in use so that there is a continuing possibility of
environmental damage (Encyclopedia Britannica, 2011).
8

Garbage
Solid waste includes paper, metal, yard trimmings, plastics, old shoes, and clothes among other
materials. This means combined sources of contaminants which contribute to atmospheric pollution
by the harmful emissions of all kinds of pollutants mentioned above.
As with the other fuels, low burning of solid waste can result in products of incomplete combustion
like particulate emissions, heavy metal vapors, acid gases and carcinogenic tars, as well as polycyclic
aromatic hydrocarbons (PAHs), carbon monoxide (CO), polyvinyl chloride (PVC), dioxins, arsenic and
heavy metals such as lead, mercury, cadmium and chromium (McCoy and Garthe, et al., n.d.).
2.1.2. Impacts on air, soil and biodiversity, water, human
All fuels used in informal brick production can cause polluting emissions to the environment and
living organisms, some are less dangerous or lethal than others, which is why it is important to gain
knowledge of their impacts and regulate their use.
The list of effects on different elements of the ecosystems is immense. In this part of the research
some effects are resumed:

Air
During their firing informal brick kilns are supplied with fuels in order to keep a constant
temperature, this activity and the reactions of the combustion generate the emission of pollutants
like those mentioned above and are transmitted into the air.
By air movement pollutants are being transported and incorporated into other elements of
ecosystems like rivers, streams, water bodies, groundwater, wells, soil, biotic elements, etc. and
eventually can become part of the food chain, affecting humans and their food resources, but in
general biodiversity also can be affected.
The most important aspect about pollutants released into the air in the case of greenhouse gases are
the effects of global warming and climate change by the accumulation of large quantities in water
vapor (H2O), CO2, CH4, CO, N2O, NOX, O3 and NO gas emissions to the atmosphere from natural
sources and anthropogenic (caused by humans) activities.
Those gases “(…) absorb and emit radiation at specific wavelengths within the spectrum of infrared
radiation emitted by the earth’s surface, the atmosphere, and clouds. The net effect is a local
trapping of part of the absorbed energy and a tendency to warm the earth’s surface” (Alam, 2006:
25).
9
There are other kinds of human made greenhouse gases such as halocarbons among others which
contain chlorine and bromine substances, and non-methane hydrocarbons (NMHC´s) and
manufactured aerosols such as chlorofluorocarbons (CFC´s) (Alam, 2006).
In the case of chemical and toxic substance emissions into the air, NOx contribute to environmental
problems like acid rain which reacts in the air to ozone (O3) and forms smog and haze.
Particular matter (PM) is a pollutant which “(…) acts as a magnet for unburned toxic materials such as
metal vapors including mercury, lead, arsenic, cadmium, chromium and products of incomplete
combustion (PICs) (…)” (Mesaros, 2007: 54). Particular matter attaches to these toxic materials and
emits them into the air.
Sulfur dioxide (SOx) contributes to acid rain and small particulate formation (PM 2.5µ) which have
negative effects on human health and plants.
Polycyclic aromatic hydrocarbons (PAHs) (naphthalene); voltaic organic compounds (VOCs)
(benzene); criteria pollutants (CP) (carbon monoxide, lead, arsenic, chromium and mercury) are toxic
emissions which are known to be cancer causing and can cause damages to the human reproductive
functions (Mesaros, 2007).
Other toxic emissions related with incomplete combustion include nickel, cadmium, xylem,
formaldehyde, and acetaldehyde among others which have unknown toxic effects on human health
and the ecosystem.
According to the Australian Department of the Environment and Heritage (quoted by Mesaros, 2007)
carbon monoxide (CO) increases methane and other greenhouse gases and oxidizes later into carbon
dioxide gas.
In the case of carbon dioxide (CO2) the environmental effect is global warming, even though much of
this gas is absorbed by plants and by the ocean surface large amounts go into the atmosphere.

Soil and Biodiversity
When ozone produced by the reaction of NOX with oxygen eventually forms nitric acid by its
dissolution in water, this acid rain can damage trees and entire forest ecosystems.
Dioxin emissions can travel long distances before settling into water or onto plants, then animals
ingest dioxins which bioaccumulate in fatty tissue and therefore pollutants can lead to human
exposure by eating food containing dioxins (Mesaros, 2007). Dioxins and dioxin-like compounds are
also persistent in soil for long periods of time. Dioxins also reduce fertility and increase sterility of
birds, fish, shellfish and mammals, and it can cause birth deformities in some cases.
10
Wood and coal used as fuel can cause among other aspects: deforestation, landslides, soil
degradation and biodiversity losses; also the constant use of primary material as soil for brick making
causes losses of agricultural land.

Water
NOx contribute to acidification and eutrophication of water bodies, and the buildup of nutrients in
coastal areas, degrading water quality and harming aquatic life (Mesaros, 2007).

Humans
Pollutants emitted by brick kiln combustions cause several health damages to humans, to those who
works in the brick production as well as to the general population.
Chemicals such as nitrogen oxides (NOX) cause several human health problems like aggravation of
asthmatic conditions, lung irritation, lowered resistance to respiratory infections, cardiac diseases
and premature mortality from acute exposure among others (Mesaros, 2007).
Some health effects associated with particular matter (PM) are premature death due to heart and
lung diseases, non-fatal heart attacks and respiratory symptoms such as coughing, wheezing and
shortness of breath, changes in lung function, changes in heart rate, irregular heartbeat (Mesaros,
2007).
Sulfur dioxide (SOX) affects human health causing respiratory and cardiac diseases as well as
respiratory symptoms. Dioxin and dioxin-likes such as furan (polychlorinated biphenyls (PCBs))
emissions can cause cancer (breast cancer, bioaccumulation of chlorinated compounds in the food
chain). Some forms of dioxin are the most carcinogenic (cancer causing) substances known to science
(Mesaros, 2007).
Dioxins levels can be reduced by the human metabolism and decompose within the body. Pregnant
women and nursing mothers pass on dioxins to their babies (Mesaros, 2007). Other health effects
caused by dioxins include”(…) hormonal disruption, decreased sperm count, descensus testis, altered
male sexual behavior, cancer, endometriosis, ovarian dysfunction, reduced fertility, immune system
suppression, spontaneous abortion, birth defects, impaired child development, thyroid changes and
diabetes” (Mesaros, 2007: 66).
Gases such as carbon monoxide can cause “(…) in small portions flu-like symptoms including
headaches, dizziness, nausea, and fatigue. In the case of mild or medium levels, of exposure,
impaired vision, and reduced brain function occurs. At high concentration levels, carbon monoxide
can be lethal as the blood begins to inhibit oxygen intake” (Mesaros, 2007: 69). Carbon dioxide (CO 2)
11
can cause asphyxiation as it replaces oxygen in human blood; other effects are headache, loss of
judgment, dizziness, drowsiness, and rapid breathing.
The effects which occur after long-term exposure to lead are decreased performance of the nervous
system, weakness of fingers, wrists, and/or ankles in the case of adults and children, anemia and
small increase in blood pressure to the middle-aged and elderly. When exposure is in high levels it
can cause severe brain and kidney damage and may result in death. Children exposed to even low
levels of lead can show slow mental development and lower intelligence (Mesaros, 2007).
2.2.
Socio-economic review of traditional brick making industry
The literature review about socio-economic conditions of traditional brick producers shows that
there are limited publications on this topic; nevertheless there exist some general observations on
the socio-economic circumstances of brick producers and a few detailed studies. This chapter gives a
review in two parts about the socio-economical conditions of the traditional brick making industry in
developing countries and especially in Mexico. The first part is about the general socio-economical
circumstances of brick making households. And the second part addresses child labor in traditional
brick industries.
The socio-economic conditions explain the lack of modernization of the brick making process (used
technologies) and help identify applicable technologies in order to formulate policies for the
promotion of these technologies.
2.2.1. Socio-economic conditions of traditional brick making industry in developing countries
Traditional brick making is an extremely labor intensive, low technology activity, generally small-scale
and lowly paid (less than the minimum wage). For instance in Ciudad Juarez, Mexico an average kiln
has a capacity of approximately 10,000 bricks, employs six workers, and generates profits ranging
around 100 USD per month (FEMAP quoted in Blackman & Bannister 1998). Socio-economic
conditions are poor, associated with the poorest sectors of communities under an economic informal
scheme and its development functions (Romo Aguilar et al., 2004).
Most of the industry is located in the periphery of urban areas (Romo Aguilar et al., 2004). The
majority of brick producers live next to their kilns in rudimentary houses with no sewers or running
water. On average kiln owners in Ciudad Juarez (Mexico) have three years of schooling and
approximately a quarter of them is illiterate (FEMAP quoted in Blackman & Bannister 1998). Studied
cases in Ciudad Juarez, Mexico show that the average age of the brick producers is 52 years (Romo
12
Aguilar et al., 2004) and in many cases brick produces have a migrant background, coming from rural
areas to cities like Ciudad Juarez and Punjab, India (Romo Aguilar et al., 2004; Singh Kainth, 2008).
Often the whole family is involved in the brick making process. Women and children may take part in
all of the main or subsidiary production steps, although they seldom mold bricks until attaining a
certain minimum skill level (Wilson, 2005). A study of traditional brick producers in Peru shows that
the father of the family is in charge of mixing raw materials and molding crude bricks. He is also firing
the kiln, while the mother helps mixing raw materials and turns crude bricks during the drying
process, and the children of the family assist by flipping crude bricks during the drying process and by
loading of the crude/dried bricks into the kiln (PRAL & Ministerio de la Producción, 2008).
Many brick kiln owners do not conduct other activities, but sometimes they combine the brick
making activity mainly with agricultural activities during the rainy season when brick production
decreases (Wilson, 2005; PRAL & Ministerio de la Producción, 2008).
According to Romo Aguilar et al. (2004) the study in Ciudad Juarez shows that the traditional brick
producers have a clear awareness on the position of the authorities in reference to produced
emissions into the atmosphere by brick kilns and the change of land use plans of the municipality.
Different strategies have been implemented: traditional brick producers have been grouped together
or joined organizations or formed cooperatives (Table 2.2.1). They have appointed leaders in order to
establish their priorities and to manage their problems with the various governmental and
nongovernmental organizations (Romo Aguilar et al., 2004).
Table 2.2.1: Number of brick kilns and organized brick producers: Ciudad Juarez, Saltillo, Torreon and Durango
Cd. Juarez
Approximate
of kilns
Organized
number
c
Saltillo
Zacatecas
a
a
Torreon
a
Durango
325
500
60
165
504b
yes a, c
yes c
no a
yes a
yes b
Source: a. Blackman, 2000; b. Hernández Camargo, 2003; c. Romo Aguilar et al., 2004
The review of different studies of the traditional brick producers realized in Mexico (Romo Aguilar et
al., 2004, Blackman, 2006) show some patterns which allow categorizing their type of engagement
(social categorization):
a. Family business
b. Worker indirectly involved in brick making mostly loading and unloading of bricks or firing
kilns
c. Temporary brick producer or "miler" who is hired by the operator (owner or person renting a
kiln)
d. Brick producer, who is owners or tenants of the land where the brick is made
13
e. Intermediary, who buys bricks to transport them in order to resell them at established selling
points or construction sites
All these categories are presented in the traditional brick industry regardless of age, sex, or social
position and continue from the extraction of raw materials to the marketing of the final product.
2.2.2. Child Labor
Child labor is both consequence and cause of poverty. Children who are incorporated in child labor
are likely to come from families affected by poverty. Recent findings show that engaging children in
child labor is a household decision to fight poverty (UCW, 2006; WVC, 2006, Bunnak, 2007).
Exhaustion to live and work, illiteracy, disease and malnutrition, psychological damage, and
premature aging are some of the consequences of child labor (WVC, 2006).
High child occupancy in informal brick production and other informal sectors has been verified in
different Latin American countries (Table 2.2.2). The table shows the worst forms of child labor. The
risks and physical damage caused by the exploitation of children mentioned in the table are: toxic
inhalations, burns, partial hearing loss, mutilation, pulmonary disorders, allergic skin disorders, and
damaged bone structures due to carrying heavy loads (Varillas, 2003:926).
Argentina
Bolivia
Brazil
Chile
Colombia
Costa Rica
Ecuador
El Salvador
Guatemala
Honduras
Mexico
Nicaragua
Panama
Paraguay
Peru
Table 2.2.2: Child labor of high risks identified by IPEC per country
brick industry, markets, leather tanneries, agriculture, manufacturing ice cream
mining, sugar production, construction, street seller, agriculture
charcoal production, quarries, preparation of sisal, scavengers
mining, agriculture, street seller
brick industry, mining, agriculture
domestic services, construction, prostitution, bananas, maquiladoras, seafood
processing
floriculture, street sellers, construction
maquiladoras, pyrotechnics, construction, coffee production, prostitution, street
sellers, scavenger
coffee production, mining, pyrotechnics, domestic work, maquiladoras, construction,
transportation, scavengers
leather tannery, bakery, maquiladoras, construction, military, pharmaceutical
industry, chemical industry
brick industry, cafes and bars, mechanical workshop, agriculture
coffee, bananas, rice, cotton, livestock, street sellers
street sellers, domestic service, sugar cane, transportation
street sellers, domestic services
brick industry, gold panning, stone cutters, slaughterhouses, construction, ,
processing coca leaf, pyrotechnics, waste, mining
agriculture, domestic service, waste, prostitution
Dominican
Republic
Source: Varillas, 2003: 927
Reliable data shows that 3,647,067 children (12.5% of the total population of children age 5 -17
years) in Mexico are working (INEGI, 2008). A substantial number of child laborers work long hours
14
and do not attend schools. For instance in Mexico 41.5% of child laborers between 5-17 years old, do
not attend school (INEGI, 2008).
In 2008 INEGI reported that almost a third (29%) of child laborers age 5 to 17 are working in activities
related to the agricultural sector. 25 % are involved in trade and selling, 24% are engaged in services,
around 14% are employed in the manufacturing sector and 6% work in constructions (Figure 2.2.1)
(INEGI, 2008).
Figure 2.2.1: Distribution of child labor according to sector and sex, 2007
100%
50220
90%
484414
80%
70%
15495
65.715
864991
380577
No specification
478846
923420
60%
50%
40%
215981
20%
Trade
444574
217484
298379
517394
30%
1503
913230
10%
Service
Construction
Manifacture industry
Agriculture
219015
1058063
144833
0%
Boys
Girls
Total
Source: INEGI, 2008
Of the 24% of children who work in manufacturing an unidentified number of child laborers are
engaged in the manufacturing brick industries which is among the worst forms of child labor in
Mexico (Ramírez quoted in Muñoz Rios, 2009). Children, especially but not exclusively male children,
from an early age are involved in carrying water, screening sand and manure, and setting up the
bricks, smoothing their edges, and carrying them to the kiln. It is often expected that sons will
become brick producers when grown up as well. Therefore they are slowly trained to work in the
more skill requiring steps. If the household sex ratio is such that a daughter’s work also becomes
necessary for family survival or economic advancement they are trained, too (Wilson, 2005). Many
brick producers perceive child labor as ‘training on the job’ which helps the family economically and
assures a future occupation for the children.
15
2.3.
Alternatives for traditional brick making industry
There are several approaches dealing with risks to humans and the environment caused by the
traditional brick making industry. This chapter presents in three parts some approaches which have
been implemented in different developing countries: 1. Cleaner Production, 2. Relocation and 3.
Opportunities for organizations of traditional brick industries.
2.3.1. Cleaner Production (CP) and traditional brick making
Cleaner Production (CP) is a prevention business strategy (method) which was originally designed to
help manufacturing companies. Meanwhile it is also applied in several other important sectors to
conserve resources, mitigate risks to humans and the environment, and promote greater overall
efficiency through improved production techniques and technologies (USAID, 2009). More precisely,
it is generally defined as "the continuous application of an integrated preventive environmental
strategy to processes, products, and services to increase eco efficiency and reduce risks to humans
and the environment"(UNEP, 1994)4.
Cleaner Production (CP) means to optimize processes in order to make more efficient use of natural
resources (raw materials, water, and energy in form of heat generated by burning fuels) and reduce
the generation of wastes and emissions at the source (Fresner et al., 2009). In addition it provides
opportunities to significantly reduce operating costs and improve product quality.
CP begins with a comprehensive look at the material and energy flow5 in a company (Thorpe, 1999),
to identify options of more efficient use of materials, energy, water and other natural resources and
to minimize waste and emissions of the business processes (processing, manufacturing, service,
transport, mining or agriculture). Organizational and technological improvements effectuate
reduction or suggestions in use of materials and energy, to avoid waste, waste water generation, and
gaseous emissions, and also waste heat and noise. Cleaner production methods may include:
1. Good housekeeping refers to changes in operational procedures and management in order
to reduce waste and emission generation. It includes spill prevention, improved instruction
of workers through training.
2. Product modifications change the product characteristics, such as shape and material
composition. The lifetime of the new product is, for instance, extended, the product is easier
to repair, or the manufacturing of the product is less polluting.
4
CP is promoted around the world by the United Nations, which supports hundreds of programs and projects
on sustainable business. The UN has produced a Status Report on CP implementation worldwide, with
extensive details: http://www.uneptie.org/scp/.
5
Where raw materials come from, how and where they are processed, which kind of wastes are generated
along the product chain, which products are made from the materials, and what happens to these products
during their use and at the end of their commercial life (Thorpe, 1999).
16
3. Input substitution refers to the use of less polluting raw and adjunct materials and the use of
process auxiliaries (such as lubricants and coolants) with a longer service lifetime.
4. Technology modifications include for instance improved process automation, process
optimization, equipment redesign and process substitution.
5. On-site recycling refers to the useful application of waste materials or pollutants in the
company where these have been generated. This could take place through re-use as raw
material, recovery of materials or other useful applications.
The promotion of Cleaner Production approaches has not been widely attempted among traditional
brick producers (Hillary, 2000). Nevertheless there have already been some Cleaner Production
efforts among brick producers in India (Hamner, 2006); and researchers have made some useful
suggestions how to improve the combustion efficiency of existing kilns, and upgrading kilns to newer
and more efficient process designs. The Table 2.3.1 lists several low-cost solutions to reduce waste
and pollution in brick making.
Table 2.3.1: Solutions to increase efficiency and reduce waste in brick production
Improve brick drying before firing
Fuel drying before firing
Good
Raise kiln temperature using improved firing techniques.
housekeeping
Stack fuel around bricks to facilitate preheating
Work regulations or safety measures
Product
Quality improvement, quality control of bricks
modifications
Switch to propane or natural gas as fuel
Input substitution
Use of alternative fuel types
Maintain kiln structure and repair cracks or leaks
Improve air flow control
Traditional brick-making technology (brick clamps)
Technology
modifications
Install filters in chimneys (rather difficult)
New kiln design (some kilns apply on-site recycling)
Mechanization of process
Source: GATE, 1995; Mason, 1998a; Hamner, 2006; Mason, 2009; USAID, 2009
In the following the mentioned solutions to increase efficiency and reduce waste in the traditional
brick production will be described more in detail.
17
2.3.1.1.
Good housekeeping
In the context of the traditional brick making operational techniques and safety regulations were
determined for the good housekeeping method. The measures shown in the Table 2.3.2 help save
fuel which leads to emission reduction as the total amount of fuel burned is reduced.
Table 2.3.2: CP – Method: Good housekeeping
Extended drying time reduces fuel requirements because less energy is used
to evaporate the bricks’ water content.
As with the bricks themselves, if the fuel contains water, then energy is
wasted to evaporate it. If using fuel wood, it should be dry and seasoned.
Raise kiln
Adding combustible material around the bricks or between clamps can
temperature using
increase temperatures and lower traditional fuel needs.
improved firing
A firing chamber beneath the ground level is more efficient than above the
techniques
ground level to raise the kiln temperature.
Stack fuel around
Solid fuel is mixed with the bricks throughout the kiln, either as sawdust
bricks to facilitate
mixed into the brick mass or as fuel channels in different levels of the kiln. By
preheating
doing this, a combustion zone can be generated in the kiln that gradually
moves upwards, using the residual heat in the lower, already burnt bricks for
preheating of combustion air. The residual heat in the flue gasses is used for
drying and preheating of the higher levels of crude bricks.
Work regulations or
Prepare a safety and health plan to minimize adverse respiratory effects and
safety measures
physical stress on kiln workers.
Source: GATE, 1995; Hamner, 2006; Mason, 2009; USAID, 2009
Improve brick drying
before firing
Fuel should be dry
The first two methods (dry bricks and dry fuels) avoid energy waste; this means that if the crude
bricks and fuels contain a lot of water when placed in the kiln, energy and money is wasted just to
dry them (evaporate the moisture content) during the firing process. Drying the input (crude bricks
and fuels) saves energy and money, since the burning process needs less time if the moisture content
of the input is less (GATE, 1995; Mason, 2009).
The following two techniques (fuel closer to the bricks and fuel in the clay mix) raise the energy
efficiency, given that if a brick is a long way from the heat source (e.g. burning fuel in a firing
chamber beneath the piled bricks ) the burning process needs more time to burn the bricks.
Incorporating, for example, coal dust or saw dust into the body of bricks and distributing the fuel
more evenly throughout the kiln are established techniques. Obviously, the fuel chosen should be
fine enough to not cause large voids in the brick surface (USAID, 2009; Mason, 2009).
The last approach is safety regulations which concern the human health. Improved safety measures
can help avoid costly accidents and worker absences (USAID, 2009).
18
2.3.1.2.
Product modification
The product modification towards more sustainable construction by promoting the use of
alternative, low-energy or renewable materials, such as earth6 or bamboo unfortunately is largely
prevented by a combination of factors: e.g. lack of governmental promotion/subsidies for sustainable
construction materials, predominant status of concrete and cement industries, increasing
urbanization, bad perception of sustainable construction materials such as adobe (construction
material of the poor), and inappropriate building standards which are generating an increasing
demand of conventional materials such as steel, bricks and cement which are all based on highly
energy intensive production processes (Schilderman, 1999).
Table 2.3.3: CP – Method: Product modification
Quality upgrade Use less fuel. Try to avoid hot-spots by distributing fuel differently.
Quality control
Technical standards, laboratory testing.
Source: Mason, 1998a
Most of the product modifications address following brick characteristics: size, shape,
strength/soundness, porosity, insulation performance, and appearance. A detailed product
modification guide for brick producers is annexed. Changes in the shape and size of bricks produced
by the traditional brick making industry in Peru have led to new products which require less raw
materials, fuels, and in addition the products have a higher quality in terms of endurance and
thermal insulation (Table 2.3.4).
Table 2.3.4: CO2 emitted by burning of bricks (m2)
Traditional kiln using wood and sawdust (Cusco)
Solid brick
Weight
2.5 kg
Dimension
24x11x7 cm
Bricks per m2
44
2
CO per m2
132 kg
Source: Bickel, 2010
Thick hollow brick wall
Weight
2.5 kg
Dimension
24x11x8 cm
Bricks per m2
40
2
CO per m2
100 kg
6
Thin brick wall block type
Weight
2.5 kg
Dimension
30x15x20 cm
Bricks per m2
20
2
CO per m2
50 kg
The production of simple earth blocks (adobe and CEB – compressed earth blocks) only requires around one
thousandth of the energy needed to fire bricks (Schildermann, 1999).
19
Nevertheless quality upgrading of the bricks are not recommended if customers aren't prepared to
pay more for improved quality, since it causes extra work and expenses for the brick producers.
Nevertheless brick producers profit if they know how to improve the quality of their product,
particularly brick producers who are unable to meet the standard their market demands (Mason,
1998a).
2.3.1.3.
Input substitution
The input substitution refers to replacing primary fuel with cleaner-burning fuels and /or costeffective fuels.
Table 2.3.5: CP – Method: Input substitution
Switch to propane or If available and competitively priced, these fuels cause significantly less
natural gas as fuel
emissions and can increase production quality and speed due to their high
calorific value..
Use of alternative
Organic wastes such as rice husks or sugar bagasse can supplement scarce
fuel types
fuel sources, such as wood without sacrificing efficiency.
Source: GATE, 1995; Hamner, 2006; Mason, 2009; USAID, 2009
Fuels, such as natural gas or propane or liquefied petroleum gas (LP gas) potentially could help
reduce emissions. However, experiences in Mexico with these fuels show that they are less effective
to reduce emissions than other approaches. The main deterrent is the elevated cost that generally
prices these fuels out of the reach of brick producers (Blackman, 1998). Improved combustion
efficiency with cheap fuels is the most practical solution to reduce emissions (TCEQ, 2002).
Some brick producers are already using residues, but not every residue is adequate 7 such fuels are
used oils8 and scrap tires, which may not fully combust in the brick kiln due to the fact that
temperatures reached in traditional kilns are not high enough. Residues which retain a high calorific
value and are cheap are recommended considering the emission factor of the material.
For instance in the Andean and coastal region of Peru traditional brick producers used exclusively
wood to fire their brick kilns (up to 8 tons of wood per kiln, depending on kiln size). Nowadays
various brick producers have changed to other fuels such as mined coal, oil, and rice husks, which are
usually more cost effective (around 30% benefit) and supplement the scarcity of wood of the region
7
According to Johnson et al. [1994], tests of emissions from traditional brick kilns burning five different fuels –
sawdust, contaminated sawdust, used motor oil, propane (old burner), and propane (new burner) – showed
the two "least desirable" fuels to be used are motor oil and contaminated sawdust. Kilns burning these fuels
emitted relatively high levels of volatile organic compounds and carbon monoxide (Blackman & Bannister,
1996).
8
The emissions from burning waste oils reflect the compositional variations of the waste oils. Potential
pollutants include carbon monoxide (CO), sulfur oxides (SOX), nitrogen oxides (NOX), particulate matter (PM),
particles less than 10 micrometers in size (PM10), toxic metals, organic compounds, hydrogen chloride, and
global warming gases (carbon dioxide [CO2], methane [CH4]) (USEPA, 1993).
20
(Mason, 2001). Secondary effect is that coal and oil cause more CO2 emissions than wood (commonly
viewed as bio fuel).
Mason (2009) and the USAID (2009) recommend organic (rice husk, sawdust, straw, maize cobs, and
animal dung) industrial residues, which might be used to partially replace fuel (coal dust, boiler waste
or pulverized coal) to reduce the costs for primary fuels (e.g. wood). The use of biomass as primary
fuel is sponsored by the United Nations to receive the benefit of carbon credits; this can increase
local economic margins and benefit to the global environment, since Mexico has signed the Kyoto
Protocol (SENER, 2005).
Table 2.3.6: Typical biomass fuels net calorific values
Moisture
Approx. Ash content
Product
(%, dry basis)
(%)
Bagasse Sugarcane
18
4
Coconut husks
5-10
6
Coffee husks
13
8-10
Corn Stover (leaves, stalks)
5-6
8
Corncobs
15
1-2
Cotton husks
5-10
3
Groundnut shells
3-10
4-14
Miscnathus
14
1-3
Oil-palm fibres
55
10
Oil-palm husks
55
5
Poplar wood
5-15
1.2
Rice hulls
9-11
15-20
Rice straw and husk
15-30
15-20
Switchgrass
8-15
6
Wheat straw and husk
7-15
8-9
Willow wood
12
1-5
Source: Schilderman & Mason, 2009
Lower Heating
Value (MJ/kg)9
17-18
16.7
16.7
17-19
19.3
16.7
16.7
19-20
7-8
7-8
17-19
13-15
17-18
18-20
17-19
17-19
An important factor for the energy efficiency of the brick making process is the type of biomass fuel
used, its moisture content, weight, calorific value, availability and its ease of use.
2.3.1.4.
Technology modification
The recommended technology modification for the traditional brick industry is based on two
strategies: a. Process optimization of traditional brick making technology and b. Introduction of new
kiln designs (Table 2.3.7).
9
Lower Heating Value (LHV): is in the case of combustion, the maximum usable amount of heat when it
does not come to a condensation of water vapor in the exhaust gas, based on the amount of fuel
used (in distinction to the calorific value, which is therefore larger than the heating value). The
heating value is called colloquially imprecise "energy content" or "energy value". It is important to
define the efficiency terms higher heating value (HHV) and lower heating value (LHV). HHV assumes H2O is in
liquid state and contains the energy of vaporization. LHV assumes gas state for all combustion products
(Bellman, 2008).
21
Maintain kiln
structure and repair
cracks or leaks
Improve air flow
control
Traditional brickmaking technology
Install filters in
chimneys.
New kiln design
Table 2.3.7: CP – Method: Technology modification
Monitor structure and machinery to identify potential leaks. Even small leaks
can substantially increase fuel costs over time.
Stopping all air leaks and controlling the kiln opening size allows better
control of air flow speed and direction to improve combustion. Maintaining a
steady rise in temperature.
Square kilns are generally more efficient than rectangular ones. Ensure
adequate insulation of the kiln and orient it at a 90° angle with prevailing
wind direction to reduce under-firing or over-firing of bricks.
Some small-scale brick producers used broken brick pieces to absorb carbon
dioxide (CO2) and reduced emissions substantially.
Vertical Shaft Brick Kilns (VSBK) allows increased production rates and
significantly decreased emissions through improved combustion air flow
efficiency. Several other kiln designs have also proven to be relatively lowcost and more efficient than traditional ovens or kilns.
Mechanization
Some processes can be (semi-)mechanized to improve the quality of the
(industrializing)
product (dispenser for bio fuels, mixing bowl for raw material etc.)
Source: GATE, 1995; Hamner, 2006; Mason, 2009; USAID, 2009
a. Process optimization of traditional brick making technology (clamp kiln):
The main purpose of the process optimization of clamp kilns is to increase the efficiency of clamp
kilns. Included in the process optimization are methods of Good Housekeeping.
It should be mentioned that a clamp kiln is by far the oldest and most rudimentary method of firing
bricks. The production of burnt clay in brick clamps artifacts dates back to 8000 BC. Despite of being
potentially the most energy inefficient method of firing, because much heat is allowed into the
atmosphere during both firing and cooling, and fuel combustion is both uncontrollable and inefficient
(Table 2.3.8), brick clamps are still used all over the world because they still have several advantages
compared to modern and sophisticated methods (Table 2.3.9) (GATE, 1995).
Table 2.3.8: Disadvantages of brick clamps
 Basic brick clamps are the least energy efficient method of firing bricks, with a lot of heat being
lost by radiation through the walls, and convection from the top of the clamp. The fuel is not
consumed efficiently as there is little or no control over its combustion once the clamp is lit. Fuel
consumption of 2,800 to 3,500 kJ/kg fired brick is to be expected, depending on the size and
design of the clamp, plus the fuel and method of combustion. This low figure is partially due to the
high percentage of broken and over or under fired bricks produced.
 They are very labor intensive, being assembled and disassembled by hand, and if not built
correctly and fired badly, can result in a very high percentage of incompletely fired bricks. Up to
20% of the bricks produced by a basic brick clamp can normally be expected to be over or under
fired by this method.
 They are very slow to fire, taking several days to heat up and cool down.
 They are highly susceptible to the prevailing weather conditions, especially strong winds, which
will result in a very uneven firing, with many more under fired and over fired bricks.
Source: Gate, 1995
22
Table 2.3.9: Advantages of brick clamps
 They are cheap and straightforward to build. There is no permanent structure to install and
maintain. A level area of ground and a good supply of fuel and green bricks is all that is required.
 They can be built next to the supply of clay and fuel, so that transport costs are kept to a
minimum.
 They can be of any size ranging from 5,000 to 100,000 bricks at a time, so they can accommodate
fluctuations in brick production.
 Once lit, they do not require much attention, especially if the fuel is included in or amongst the
bricks in the clamp.
 Very large brick clamps can be fired continuously, with fired bricks being unloaded at one end of
the clamp and green bricks loaded at the other, while the fire moves through the middle. The
result is a continuously firing clamp.
 Clamps can be fired with a large variety of fuels, including agri-waste, such as rice husk, coffee
husk, sawdust, coconut husk, dung, etc, as well as fossil fuels. Different fuels can be used at
different stages of the firing and in a variety of ways. They can be mixed into the green bricks,
sprinkled around them, placed in layers between them, or burnt in the tunnels under the clamp. It
depends on fuel price and availability, as well as on its calorific value, which determines the
amount needed.
 As wood fuel becomes scarcer and more expensive, agri-waste or any suitable combustible
rubbish can be used, at least for the first heating and drying stages of the clamp firing. For
example, the clamp can be started with slow burning rice husk, to provide a gentle heat that needs
little or no attention overnight. Then coconut husk is used to move the temperature through the
middle ranges. And finally, split rubber wood is used to provide the top temperature and soaking
period.
Source: taken from Gate, 1995
Applying some basic modifications in the construction of the clamp kiln (Figure 2.3.1), can increase
the energy efficiency. For instants the efficiency of a square kiln is better than a rectangular one of
the same volume because it has a smaller exterior surface and therefore reduces heat losses (Mason,
2009).
Figure 2.3.1: A basic brick clamp
Source: GATE, 1995
Another important modification to lower the required amount of fuel and produce less under fired
bricks can be achieved by providing the maximum amount of insulation around the outside. Ticker
walls or a wall with an air gap are recommended or using the partially fired bricks from a previous
firing to surround the bricks in the centre of the clamp, surrounding these in turn with closely fitting
23
layers of fully fired bricks and smearing10 (scoving) the whole outside with a thick layer of clay,
combined with ash, rice husk or dried grass improve the performance of the kiln (Figure 2.3.2) (GATE,
1995; Mason, 2009).
Figure 2.3.2: Insulation of a fired scove clamp/kiln
Source: GATE, 1995
Controlling the airflow (speed and direction) helps improve fuel combustion and cut down on heat
wastage. This can be achieved by compressing leaks (CP: housekeeping method) of the kiln and
opening and closing gradually the firing tunnel. It is also recommended to stoke regular small charges
of fuel into the kiln, than to over-fill the combustion tunnels with large amounts of damp fuel at
widely spaced irregular intervals. Kiln temperature should rise quite slowly and constantly11, which
means that the maximum air amount should be allowed in after fuel is added (vents are fully open,
to allow all the water vapor out of the kiln quickly) and then the size of the vents can be reduced
once the fuel is burning well and at the end of the firing the tunnels are sealed of completely
including the vents at the top of the kiln and allowed to cool slowly (GATE, 1995; Mason, 2009).
The major loss from most kilns is due to too much cold air being drawn in, hence the next stage
towards improved fuel efficiency is to build the kiln so that the firing tunnels are at a 90o angle to the
prevailing wind, to protect the fires from cooling winds (USAID, 2009).
b.
Introduction of new kiln designs in the traditional brick industry
During its 6,500 years of history of firing bricks, humankind has used a large variety of kilns. Over the
years, brick kilns have basically evolved from rudimentary “intermittent” kilns as the traditional
clamp kilns to more complex, energy-efficient “continuous” kilns (Heierli & Maithel, 2008). Clamp
kilns can be made moderately efficient, but they cannot compare with up draught continuous kilns,
10
The encasing of a brick clamp in a plaster of clay is called scoving. Clamps sealed and insulated in this way
(GATE, 1995).
11
Too much air will cool the bricks and waste energy, too little air and the fuel will not burn completely
(Mason, 2009).
24
as far as fuel used per fired brick and brick wastage is concerned. Continuous kilns typically use waste
heat to pre-heat bricks and don't need to be heated up for each batch of bricks. While clamps lose
combustion gases because they are fired intermittently12 (UNHABITAT, 1991; GATE, 1995; Mason,
2009). It is important to compare the range of kiln types and their energy efficiency.
According to Barriga et al. (quoted in Schilderman, 1999) the theoretical energy requirement to fire
bricks has been at 0.85 MJ/kg of fired brick. The data collection of the energy efficiency by kiln and
fuel types shows the energy use in practice (Table 2.3.10).
Continues
Interm
ediate
Table 2.3.10: Energy use and efficiency by kiln and fuel types
Energy use (MJ/kg
Kiln types
Fuel types
Energy efficiency (%)
fired brick)
Traditional clamp
Biomass
3.0 – 8.0
10- 28
Intermediate kiln
Coal, coke
2.0 – 4.5
19 - 42
Scotch kiln
Biomass
1.5 - 7.0
12 - 59
Vert. Shaft kiln
Coal, wood
0.7 -1.0
60 – 90
Habla kiln (Zig-zag)
Coal…
0.8 – 1.1
75
Bull’s trench kiln (BTK) Coal….
1.1 – 4.0
21 - 77
Hoffmann kiln (HHK)
Coal, gas, oil
1.5 – 4.3
20 - 56
13
Tunnel kiln
Oil, gas
1.5 – 2.0
45 - 56
Source: Schilderman, 1999; Hamner, 2006; Heierli & Maithel, 2008
The introduction of new kiln designs in the traditional brick industry would reduce the CO2 emission
and other emissions (GHG). More information about the kiln designs is found in the Appendix 1.
For a variety of reasons Replacement of intermittent kilns by continuous kilns is not always possible:

The demand may not be large enough to justify continuous production.

The capital cost of continuous kilns is higher.

The amount of land needed may not be available.

The technology for clamp burning is simpler, particularly when only biomass fuels are
available (UNHABITAT, 1991).
c. Mechanization generates maintenance costs and trained workers are required.
Semi-mechanization of the brick forming process along with introduction of efficient kilns, can
improve the quality of bricks, reduce energy consumption, and reduce drudgery of the workers
(Heierli & Maithel, 2008).
12
More information about the differences of intermediate and continues kilns are found in the Appendix 1.
Tunnel kilns are the most common kilns in industrialized countries. In tunnel kilns, the bricks move through a
"tunnel" on a cart. They are usually highly mechanized and require substantial investments. (Heierli & Maithel,
2008).
13
25
2.3.2. Relocation of traditional brick kilns
Air pollution caused by the traditional brick industry increases concerns about possible negative
health effects on nearby residents. With the aim of reducing the impact on the close by population
some states are implementing programs to relocate the traditional brick industry further away from
settlements (e.g. Guanajuato, Jalisco, and Chihuahua etc.) (CENICA, 2008).
These state programs mostly determine the relocation area by one factor: the brick making industry
should be relocated in the periphery of the urban agglomeration. In most cases the city selects a
public terrain as the site for the relocation and later entrusts the property to the brick makers. Often
the transport situations from the districts where the brick producers live to the new location or
“industrial brick park” (parque industrial ladrillero), accessibility of water, neither social nor
economical conditions14 are taken in consideration during the determination of the relocation area
(Romo Aguilar et al, 2004; González Roldán, 2006). It is obvious to assume that relocating kilns to
unpopulated areas outside the city will lessen the direct effects on the health of the community, but
it is also critical to assess whether such a move is economically and politically feasible. Otherwise,
such a program will eventually fail and will only upset the involved parties.
One has to have in mind that with the relocation of their kilns the brick producers take huge
existential risks.
According to the results of a survey of 95 brick kilns in Ciudad Juarez, 53% of their owners live within
a 100m radius (Blackman and Bannister, 1998). This indicates that such activity is the economic
mainstay of a significant proportion of the population in surrounding areas, which would be
significant opposition to any relocation attempt (because they would have to bear the costs of
moving physically to another place, which would increase operating costs by having to travel to a
distant area, etc.) (Romo, 2005).
The approach considering these circumstances to determine the new area to relocate the undesired
kilns focuses on two objectives: it should be situated as far as possible from settlements in order to
avoid negative health impacts on the population and the second requirement is that the location
should be located as close as possible to suppliers of raw materials in order to achieve an operational
efficiency (Ruvalcaba & Correa, 2009).
14
Expenditures are mainly not contemplated, such as existing economic commitments with suppliers,
customers and leaders or transfers, which further complicate the situation for those located far away from the
new location (Romo Aguilar et al., 2004).
26
Ruvalcaba & Correa (2009) present mathematical models (Atmospheric diffusion models15: Gaussian
distribution, Pasquill-Gifford table) to calculate an appropriate distance between the affected
population, suppliers and the possible new location for brick kilns. Procedure for the finding of
possible relocation area in Yahualica, Jalisco:
1. Three possible relocation areas were identified which are located at least one kilometer away from
Yahualica and account of at least 2000 m2.
2. The size of each population close to the possible relocation areas was determend.
3. The distance between the possible relocation areas and the closest population and supplier was
calculated.
4. The composition of the smoke emitted by the combustion of the kilns was analyzed.
5. Application of atmospheric diffusion model for each gas considered harmful.
6. Formulation and solving of a mathematical model using LINGO v.10 (Optimization modeling tool
for linear, non-linear, and integer programming).
7. The results were interpreted and communicated with the brick producers. The chosen location for
the relocation is located 3.5 km from the closest settlement and 1.05 km from the closest supplier
(Ruvalcaba & Correa 2009).
In order to determine a justified distance between informal brick kilns and the closest population the
combustion smoke of the the kilns has to be analyzed and a spatial diffusion of each contaminating
gas has to be calculated, also the geographical aspects have to be taken in consideration (wind,
water, accessibility etc.).
The work between state authorities, universities and the brick producers has shown another
approach to determine a new location for the brick producers: Certain factors are important to
determine the best area for the relocation of traditional brick making industry according to Corral
Avitia et al. (2010) Researchers of the Autonomous University of Ciudad Juarez who analyzed
adequate locations for the brick makers in Ciudad Juarez selected indicators which include
biophysical, economic and social categories illustrated in Table 2.3.11. These 16 indicators with
standardized weighted data were digitally mapped in GIS using the Spatial Analysis® extension in
order to generate distance corridors in the maps16. In addition it should be mentioned that climate
15
The transport and diffusion models of pollutants are numerical or physical representations of the behavior of
gases or airborne particles, which allow a quantitative determination of the concentration of pollutants
emitted by stationary sources (Ruvalcaba & Correa, 2009).
16
Map algebra polygons were obtained with different degrees of vulnerability or risk to the population and the
ecosystem. With this vulnerability map the impact of the traditional brick making industry was assessed (Corral
Avitia et al., 2010).
27
and topography are important factors in the formation and transport of air pollution (Rincón et al.,
2005), which should be considered in the analysis of the adequate new location.
Table 2.3.11: Example for Ciudad Juarez: Categorized indicators for
the analysis of possible relocation areas for the traditional brick
making industry
Category
Subcategory
Factor
Vulnerable Species
Biological
Ecological Zones
Groundwater Hydrology
Environmental
Surface hydrology
Physical
Elevation
Pedology
Slope
Geology
Economy
Construction
Land use
Roads
Residents
Population
Housing
Fuel storage
Social
Airports
Sensitive elements
Border limits
Transmission lines
Source: Corral Avitia et al., 2010
It is important to mention that if relocation is feasible, it should be implemented through command
and control measures to ensure compliance. However, the socio-economic background of the brick
producers does not allow major changes, which also makes any initiative to improve and relocate the
brick kilns difficult (Romo Aguilar et al, 2004). Relocation programs also require government
investment in order to establish the necessary common infrastructure in the area where the
relocation is intended to be carried out (Romo, 2005; Castro, 2010). In addition, it is important to
indicate that the action of relocation projects initiated by authorities has created distrust in the
group of brick producers and animosity towards any stranger, who intends to apply research in the
traditional brick industry. This is because past experiences have shown that possible implementation
of changes threaten the stability of the trade development and therefore their only source of income
(González Granados et al., 2008; Barrientos, 2010). Nevertheless some projects of industrial brick
parks have shown efficiency in terms of economical benefits (Table 2.3.12): brick makers in Durango,
Mexico who have moved to an industrial brick park sell a million bricks on a monthly basis and have
attracted customers who buy up to ten million bricks per year (construction companies working for
the National Chamber of Housing Developers) (El Siglo de Durango, 2007).
28
Table 2.3.12: Benefits of relocation
Economies of scale could improve the operation of the entire sector by acquiring mills
and mixers etc. of larger scale.
Improved performance of the sector which faces competition from other products,
quality problems and lack of capacity
Competitive
Establishment of quality systems and development of new products, such as Mexican
advantages
tiles.
The site would be located in a strategic place to optimize distances to areas of raw
materials and selling points.
A training center could be installed at the site in order to have immediate technical
advice.
The environmental monitoring would be easier and would ensure the proper
functioning of the kilns.
Environmental
The site could be located in undesirable areas for housing in order to avoid the
advantages
development of settlements.
Ensure compliance with emissions trading conditions.
Source: González Granados et al., 2008; Barrientos, 2010
2.3.3. Organized traditional brick maker
In most cases the brick producers have a trade organization that represents them (such is the case
with the brick producers of Tercera Chica, Saltillo and Ciudad Juarez) and has been active in
implementing programs to reduce pollution. However, there are other cases (e.g. in several
municipalities in the state of Puebla) in which such associations do not exist, which has halted any
attempt to implement programs due to the difficulty of contacting all the individual producers
(Romo, 2005).
Nevertheless, many brick producers are open minded towards alternative mechanisms such as
cooperatives, organization and participation initiatives to undertake joint sales, making it possible to
buy raw material in larger quantities and therefore at lower prices, and to supply clients with higher
demands; they group together or join an organization, and even appoint leaders to establish their
priorities and to manage their problems with the various governmental and nongovernmental
organizations (Romo Aguilar et al, 2004). Various events such as meetings and visits to other brick
producers exchanging experiences favor the continuation and consolidation of these cooperatives.
The organizational component is central for the strengthening of the local nucleation and its regional
and national contributions. The fact that producers are clustered into chambers or cooperatives can
facilitate the implementation of programs designed by the authority, as it will have a partner to help
carry out advocacy and dissemination of relevant information (Table 2.3.13). Also should be
mentioned that the more competitive the sector (i.e. the more fragmented the market), the greater
the importance of such a cooperative. In addition it is more practical to channel information through
a single instance to try to contact a large number of small producers (Romo, 2005).
29
There is not much information available on the form or models of cooperatives 17 used by brick
producers, but there have been identified mainly two groups on their way of organizing an
association: those who are not members of a labor union party and those who are members (Romo
Aguilar et al, 2004).
Table 2.3.13: Some benefits of an association/cooperative
Common operation
Common infrastructure
Working together, buy the raw materials and improve economically
Access to wider markets
Improved
Mechanization (machines can be bought together)
product quality
Clean technology affordable
Capacitating workforce
Increased
Access to clients with higher demands
customer
Common customer base
Common distribution channels
Increase sales
Access to wider markets
and revenues
Common brand equity (marketing)
Common trust (perceived stability)
Clean technology venture not only in terms of environmental responsibility, but in terms of
streamlining the process and better use of resources, which makes the cooperative become
more competitive.
Organization
A cooperative can represent their interests to other unions, consumers, and authorities.
Since the market is highly competitive, implement the ban on highly polluting fuels (tires,
plastic, etc.) in order not to disadvantage producers who choose to join the program in the
initial stage. Similarly, establish, in conjunction with the association, a timetable for the
transition to cleaner fuels.
Identifying synergies with other local industries that can result in mutual benefits18.
Cooperation between associations.
Subsidies
State and municipal programs designed by authorities (green subsidies and capacitating
programs
workforce).
Clean Development Mechanism (CDM): Use of environmental certification procedures
(carbon credits). The Certified Emission Reduction (CER) allows easier access to
technological change in developing countries especially for small and medium-sized
businesses interested in contributing to the reduction of emissions.
Source: Fernández Flores & Moguel Rodríguez, 2004; Romo, 2005; SENER, 2005; Barbosa, 2008; Castro, 2010;
Leyva, 2010; Martínez, 2010
Increased
production
However, it is also necessary to note that a strong and united group of brick producers may also be a
source of resistance to change unless their support can be obtained. Industrial cameras in the
industry can play an important role but there is a danger that the leaders are more concerned with
17
The cooperative is a form of social organization composed of people with a basis of common interests and
the principles of solidarity, self-help, and mutual aid in order to meet individual and collective needs, through
the implementation of economic activities such as production, distribution and consumption of goods and
services (Art. 2 of Ley General De Sociedades Cooperativas, DOF 13-08-2009).
18
An example of this kind of synergy has been experienced by brick producers in Saltillo. In this case, a kiln was
designed that uses recycled motor oil as fuel. Using recycled motor oil as fuel obtained from mechanical
workshops reduced the amount of oil discharged into the drainage and other unauthorized sites. Brick
producers in cooperation with mentioned mechanical workshops have found a fuel which was previously a
waste material (Romo, 2005).
30
reducing the burden of existing regulations then to address goals of long-term environmental
sustainability (Romo, 2005).
31
3. Methodology
The methodology is described in three parts: the data collection, the data analysis, and a literature
review of the applied methods featuring the background of the methods. It should be mentioned
that the conceptual framework was mainly used as a base or as secondary data for the participatory
workshops.
3.1.
Data collection
3.1.1.
Secondary sources
The investigation includes a literature review which concentrates on the informal brick making sector
world-wide, and especially in Mexico. Secondary sources such as scientific publications, scientific and
institutional reports, investigations, and other literature resources available were taken into account.
Furthermore maps of the city of San Luis Potosi were used.
The literature review shows that there are limited publications on the topic informal brick making;
most of the investigations do not have specific values about the amount of pollutants emitted by
informal brick production. The reviewed literature concentrates manly on policies, socio-economic
conditions, and technical alternatives.
3.1.2.

Primary sources
Questionnaires
Semi-open surveys were used to interview the informal brick producers of Tercera Chica. Two
different surveys were developed and deployed:
A. Socio-economic evaluation of brick producers: the survey is divided in four parts I) General
data II) Health condition, III) Dwelling, IV) Revenue. The survey consists of 30 questions.
B. Evaluation of informal brick production: the survey consist of six parts I) Kilns, II) Cost of brick
production, III) Existing brick production site, IV) Analysis of the brick demand, V) Labor data,
VI) Membership, VII) Implemented or attempted improvements in brick production and VIII)
Relocation; Te survey consist of 46 questions.
At the end of the second workshop which took place December 5th 2010, 40 questionnaires were
issued to all 40 present members of Grupo Ladrillero y Artesano la Tercera Chica. The following day
25 questionnaires were returned.

Collection of GPS points of traditional brick kilns and selling points
In November 2010 a list of all members of Grupo Ladrilleros y Artesanos la Tercera Chica A.C. issued
by representatives of the cooperative was used to locate the kilns of the members. Fifty seven kilns
32
were located using a Global Position System (GPS) tracker. Due to the fact that the issued list wasn’t
up to date 3 kilns weren’t located. Kilns belonging to informal brick producers who are not members
of the cooperative were not located due to either lack of cooperation or difficulties in establishing
contact. Also all four mayor selling points of informally produced bricks throughout the city of San
Luis Potosi were located with a GPS-tracker.

Inventory of traditional brick kilns
An inventory of the 57 kilns owned by members of Grupo Ladrilleros y Artesanos la Tercera Chica
A.C. was accomplished documenting the capacity, geometry, condition, and orientation of firing
chamber accesses.

Non-participative observation
For this part of the investigation a non-participative observation method was used. The brick
production process was documented observing each production step using the help of one informal
brick producer explaining his production process which is basically the same throughout Tercera
Chica. Also each production step was documented by photography. Contact was established through
the spokesman of the cooperative Grupo Ladrilleros y Artesanos la Tercera Chica A.C. Juan Gutiérrez.

Participatory workshop (Participatory Action Research methods - PAR)
The present research is not aiming to be a complete participatory action research (PAR) there was
just not enough time to analyze, write, and evaluate all outcomes of the investigation. But some of
the common methods and techniques of PAR were used involving the focus group (brick producers of
Tercera Chica who are members of Grupo Ladrilleros y Artesanos la Tercera Chica A.C.) to achieve
some practical outcomes. The participants of the participatory workshops were local traditional brick
producers, members of the above mentioned cooperative. Convocation of the workshops was made
by the president of cooperative.
Two participatory workshops were realized with following techniques:
I. Participatory workshop:
The 1st participatory workshop was performed on 7th of November 2010, 38 of 76 members of the
brick producer’s cooperative were present in the assembly room of the cooperative.
Alternative approaches to improve the energy efficiency (improves the economical profits and
lessens contamination of brick making) and complementary strategies for traditional brick producers
to improve organizational conditions and lessen contamination on affected neighborhoods were
presented in a prepared power point presentation. The conceptual framework of the investigation
33
served as a base for the participatory workshop. The data of the conceptual framework was first
presented and then reviewed with the participants by analyzing and discussing it with the group.
 Presentation of approaches
Following approaches were presented:
a. Clean Production-methods: good housekeeping, product modification (bricks), input
substitution (fuels), mechanization, and new kiln design.
b. Complementary strategies: relocation and cooperatives.
 About good housekeeping
Ten actions of good housekeeping were explained during the presentation:
Table 3.1.1: Participative workshop topics: Ten actions of good housekeeping
Heat loses through kiln walls. Big kilns are more efficient then small kilns due to the better ratio of
volume to external surface.
Heat loses thru kiln walls. Squared kilns are more efficient than rectangular kilns due to better ratio of
volume to external walls.
Heat loses thru kiln walls. Better insulation measures like thicker kiln walls, covering internal surfaces
with plastering and walls with air gaps.
Heat loses thru kiln walls. Fuel should be as close to bricks as possible during firing (surrounding them).
Even could be mixed with raw materials.
Bricks should be dried properly before firing in order not to use energy in form of heat to evaporate the
water content.
Fuel should be dry in order not to use energy in form of heat to evaporate its water content.
Kiln control should be applied as often as possible. Temperature should rise slowly. Air flow control
should be regulated because too much air entering the kiln cools down the bricks and too little air will
cause an incomplete firing of the fuel.
Alternative fuels like agricultural residues should be used.
The entrance to the firing chamber should be located at a 90 degree angle to the dominant wind
direction. This way over and under firing is prevented.
Continues kilns should be applied due to their high efficiency in terms of fuel consumption.
 About product modification
Suggestions of brick modifications (size, form, weight, material, color) were made to diversify the
product scale. The benefits of brick modifications were reviewed.
 About substitution inputs (fuels)
Biomass fuels as a fuel substitution for plastic wastes and tires were discussed. Type of biomasses
which could be available in the state of SLP were reviewed.
34
 About mechanization and new kiln design
Mechanization: A metering machine (dosificadora) of solid waste was introduced (operation,
efficiency and price) and a commercial video of the metering machine from PMT Grupo Industrial
(duration: 5 minutes) was shown to discuss the potentials, challenges and experiences of the
adaptation of this (semi)mechanized production step.
Kiln design: different kiln designs were shortly presented. A detailed review of the Vertical Shaft Brick
Kiln (VSBK) was given. Two videos with more detailed information on the VSBK were shown. Each
video had duration of 8 minutes. The first video, an animation by Said Attar (2006), showed the
technical features and functionality of the VSBK. The second video “Horno demonstrativo para
ladrilleras artesanales” by PRAL (2009) showed the experience of traditional brick producers from
Arequipa, Peru working with the newly introduced VSBK.
 About complementary strategies: relocation and cooperatives
Advantages and disadvantages of relocation programs and cooperatives were shown. In addition two
approaches which consider these circumstances to determine the relocation sites were shortly
explained; one approach of Ruvalcaba and Correa (2009) and another one by Corral Avitia et al.
(2010). This was done in order to indicate that a new site for a brick industry park needs to be chosen
considering different factors such as the opinion of brick producers, distance to the affected
population, necessary infrastructure, etc. (see conceptual framework).
An introduction for possibilities of receiving economical support from governmental institutions and
examples from ongoing projects concerning clean development mechanisms (CDMs) were presented.
II. Workshop: SWOT
Detailed questions asked by the brick producers which couldn’t be answered in the first workshop
were answered in a power point presentation.
Each approach presented in the first workshop was briefly summarized. Then the SWOT-analysis
(Strength, Weakness, Opportunity, and Threat-analysis) was explained and used to document and
analyze the brick producers’ perception of each approach. This was done using a prepared power
point presentation showing the following table for each approach.
35
Table 3.1.2: SWOT Matrix used for participative workshop
Strengths:
Weaknesses:
controllable
Opportunities:
Threats:
uncontrollable
Strengths, weaknesses, opportunities, and threats were documented. Then necessary actions to
convert weaknesses into strengths and threats into opportunities were elaborated together. The
participatory workshop contributed to the generation of the results but the analysis of the results
was made by the researcher as well as the conclusions and recommendations.
3.2.
Analysis of information
 Analysis of questionnaires
The questionnaires have been analyzed quantitatively with descriptive statistics using Excel.

GPS: Aggregation of GPS points to existing GIS maps of San Luis Potosí
The gained GPS data from the field work was used to generate a map indicating the locations, size,
and condition of 57 kilns and 4 selling points. This was accomplished with the help of Luis Alberto
Olvera Vargas of the Coordination for Innovation and Application of Science and Technology, UASLP.

Evaluation of kiln conditions (inventory of kilns)
In order to evaluate the condition of each kiln following four categories were created:
Condition
Very good
Good
Poor
Very poor
Table 3.2.1: Indicators to evaluate conditions of kilns in Tercera Chia
Description
No cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
Many cracks in kiln walls, kiln structure damaged
Kiln walls are severely damaged, supporting structure is applied
Also the located kilns were evaluated using cleaner production (CP) approaches concerning the
geometry (rectangular or quadratic), the orientation of the firing access, and location of the firing
chambers (beneath or above ground level).
36
 Non-participative observation
The results of the non-participative observations have been documented and analyzed using
scientific literature (conceptual framework) about emitted contaminations during the brick making
process and CP-methods to improve the energy efficiency, which can improve the economical
benefits and lessen the contamination of the environment.
 Participatory workshops
I. Participatory workshop: Group discussion
Every approach was analyzed and discussed with the participants (members of Grupo Ladrilleros y
Artesanos la Tercera Chica A.C.). The discussion was audio-recorded. After every approach the group
had time to ask questions and express their opinions and share its experiences with each approach.
The results were quantitative analyzed.
The first workshop was an introduction of approaches in order to find out in a participatory action
which approaches could be accepted and applied in the traditional brick industry of Tercera Chica.
The conceptual framework of this investigation was analyzed and discussed with the traditional brick
producers. Indicators of the analysis during the first workshop have mainly been a. feasibility of the
presented methods and strategies, b. experiences with presented methods and strategies, c.
awareness / knowledge about the presented methods and strategies and d. opinions about
presented methods and strategies.
II. Participatory Workshop: SWOT
During the second workshop more secondary data has been gathered about the CP-methods and
complementary strategies which were analyzed with the group using the SWOT-analysis.

SWOT-analysis
The goal was to audit the presented methods and strategies (CP-methods and complementary
strategies) using SWOT. Identifying key internal and external issues which allow brick producers in
Tercera Chica to carefully consider and incorporate strategic objectives.
1. The SWOT analysis was explained using an example.
2. After every presented topic the group discussed the suggested strategy options (CPmethods, relocation and cooperative) and placed responses in each of the quadrants. Every
topic was analyzed by examining the internal strength and weaknesses (personnel, facilities,
location, products and production, services) the presented strategy/method could have by
applying it to the brick production in Tercera Chica. Afterwards the external opportunities
37
and threats for the same method were examined by abstracting the effect of the application
of the strategy/method on the political, economic, social, technological, and competitive
environment.
3. Finally the participants were asked to reflect their results of the SWOT analysis to each
presented strategy/method.
3.3.
Review of methodology
3.3.1. Observation
Observation is the process of observing behavior and a form of naturalistic inquiry19, which allows
investigation of phenomena in their naturally occurring settings. Observational methods provide
accurate information and results that are not reported by participants themselves, but collected
directly by the researcher. It aims to understand the context and activities of the researched as they
naturally occur which involves the collection, interpretation and comparison of data. It usually
involves quite lengthy periods of time at the study area. The detailed observation allows gaining
information in form of notes, records or audio or video recordings with the object of evaluating a
system. To avoid the loss of specific information the researched is often asked to describe their
action during the interaction (this technique is called “thinking aloud”) (Alston & Bowles, 2003;
Evaluating Socio Economic Development, 2009).

Observation methods
Structured observation specifies precisely what should be observed and how. The researcher
systematically observes certain pre-defined behaviors and uses a predetermined set of observation
categories (Alston & Bowles, 2003).
Non-structured observation makes no specific rules about the observation procedure and is a more
qualitative method because there is no careful plan and no organized categories of observation units
(Alston & Bowles, 2003).
Participative observation (ethnography) involves the researcher as an active part of the research
situation, participating in all activities and interacts with the researched. The extent of the
involvement of the researcher must be assessed before research begins in an observation study
(Alston & Bowles, 2003).
Non-participative observation is an observation method where the researcher is not participating in
the behavior or situation being examined (Alston & Bowles, 2003).
19
Another form of naturalistic inquiry that complements observational methods is conversation and discourse
analysis (Evaluating Socio Economic Development, 2009).
38
Table 3.3.1: Observation methods
Structured observation
Unstructured observation
 Quantitative
 Qualitative
 Carefully planned
 Flexible research plan
 Behavior type observed and carefully defined  No preconceived ideas about what behavior
 Categories developed
is to be observed
 Time period determined
 Categories developed during the study
 Observation study completed
 Time period determined
 Used mainly in explanatory research
 Observation study completed
 Used mainly in exploratory or descriptive
research
Participant observation
Non-participative observation
 Researcher is part of the study situation
 May be quantitative or qualitative
 Ethical considerations require disclosure
 Can decide what is to be recorded or can
 Must assess effect on research situation of
have a flexible research plan
disclosure
 Can decide what is to be recorded or no
 May be quantitative or qualitative
preconceived ideas about what behavior is
 Must decide what is to be recorded
to be observed
 Time period determined
 Time period determined
 Note that presence of participant observer
 Observation study completed
may influence the behavior being studied
 Observation study completed
Source: Alston & Bowles, 2003:194-197
Table 3.3.2: Strengths and weaknesses of observational methods
Strengths
Weaknesses
 Observation methods allow data to be  The reliability of the observation depends to a
gathered in difficult situations where other
large extent on the professional know-how of
survey techniques cannot be used.
the researcher.
 Unexpected data can be captured which other  Observation requires careful preparation to
methods could miss.
enable the observer to fit into the observed
 Observation methods are limited to a small
context without disturbing anyone, as well as
number
of
settings
which
makes
considerable time for data collection is needed.
generalizations difficult.
 Non-structured observations: A risk of selective
perception
 Participative observation: A risk of "overidentification" with the environment being
studied, i.e. the observer becomes less
objective.
Source: Alston & Bowles, 2003; Evaluating Socio Economic Development, 2009
3.3.2. Participatory Action Research (PAR)
The participatory action research (or action research) has been defined “as a collaborative process of
research, education and action” (Hall in Kindon, Pain & Kesby, 2007) in other words it is research
which pursues action (change) and research (knowledge or understanding) at the same time (Bloor &
Wood, 2006) and “is explicitly oriented towards social transformation” (McTaggart Kindon, Pain &
Kesby, 2007).
Many writers on participatory action research trace its origin to Kurt Lewin (1946) who argued that
social science should be concerned with addressing goals. The method is a socially engaged approach
to knowledge generation (Reason & Bradbury, 2001; Bloor & Wood, 2006). Action research
39
represents “a major epistemological challenge to mainstream research traditions in the social and
environmental sciences”, involving people as agents of their own development as an alternative to
development surveys (Kindon, Pain & Kesby, 2007).
Table 3.3.3: Characteristics of PAR
Key characteristics of PAR
Participatory Action Researchers are generally:
 Aims ‘to change practices, social structures, and  Hybrids of scholar/activist where neither is
social media which maintain irrationality, injust
privileged.
and unsatisfying forms of existence’ (McTaggart  Interdisciplinary.
1997 quoted in Reason and Bradbury 2006: 1).
 Mavericks/heretics.
 Treats participants as competent and reflexive  Patient.
agents capable of participating in all aspects of  Optimistic, believing in the possibility of
the research process.
change.
 Is context-bound and addresses real-life  Sociable and collaborative.
problems.
 Practical and concerned with achieving real
 Integrates values and beliefs that are indigenous
outcomes with real people.
to the community into the central core of  Able to be flexible and accommodate chaos,
interventions and outcome variables.
uncertainty and messiness; able to tolerate
 Involves participants and researchers in
paradoxes and puzzles and sense their
collaborative
processes
for
generating
beauty and humor.
knowledge.
 Attracted to complex, multi-dimensional,
 Treats diverse experiences within a community
intractable, dynamic problems that can only
as an opportunity to enrich the research process.
be partially addressed and partially resolved.
 Leads to the construction of new meanings  Engaged in embodied and emotional
through reflections on action.
intellectual practice.
 Measures the credibility/validity of knowledge
derived from the process according to whether
the resulting action solves problems for the
people involved and increases community selfdetermination.
Source: Kindon, Pain & Kesby, 2007:14
Action researchers find themselves often in the position of simultaneous roles of an academic and
activist, instead of maintaining a distance between themselves and the research problem in order to
remain free of bias (Table 3.3.4).
Features of action research are public participation (including participative workshops) which are
implemented in the present research. The public participation or the participation of the focus group
in a research supports that changes are usually easier to achieve when those affected by the change
are involved (Table 3.3.4) (Bloor & Wood, 2006).
40
Table 3.3.4: Some strengths and weaknesses of participatory action research
Strengths
Weaknesses
Most effective way of generating Disappointment if changes are not
commitment
to
action
among implemented, which may result in hostility
stakeholders.
or skepticism towards other projects.
Empowerment of stakeholders.
Encourages stakeholders to reflect and
seek to improve services.
Involves stakeholders in gathering data
about their own questions.
Participants
(focus group/ Enables stakeholders to ask and answer
important questions.
stakeholder)
Control over how the research affecting
their lives.
Owners of design, process, and results.
Learn research skills.
Build relationships and networks.
Recognition of different perspectives reduce conflict.
Rapid primary data generation.
Risk of bias (loss of reliability of the
research).
Broad involvement can make establishing
common ground more difficult.
Time-consuming.
Broader data analyses and effective
dissemination strategies
Reduce the gap between research and
practice.
Research
Pertinent client-based research
questions and acceptable interventions.
Increasing the chances of success and
usefulness of the research
Verify assumptions about the outcome
Source: Krishnaswamy, 2003; Bloor & Wood, 2006; ESSQ, 2008

Methods and techniques
The most common methods used in action research focus on dialogue, storytelling, and collective
action (Table 3.3.5). Participatory methods and techniques focus on shared learning, shared
knowledge, and flexible and structured collaborative analysis (Kindon, Pain & Kesby, 2007).
Table 3.3.5: Common methods used in PAR
Participatory
Participant observation
workshops
Surveys
Learning by doing
Community art and
Diagramming
Media
Exchange programs
Educational camps
Ranking and scoring
Secondary data analysis
Shared writing
Shared presentation
Source: Bloor & Wood, 2006; Larkin, 2006
Group
work
discussions
Dialogue
Mapping
and
Political action
Interviewing
Educational camps
Shared analysis
3.3.3. SWOT analysis
The SWOT analysis is a tool for situation analysis and strategy development. A SWOT analysis
combines the strengths and weaknesses analysis and the risk -reward analysis. SWOT analysis has its
41
origins in the 1960s (Dyson, 2004). SWOT is an acronym for Strengths, Weaknesses, Opportunities,
and Threats. It relies traditionally on a quadrant figure (Figure 3.3.1).

Strategy development
Figure 3.3.1: Traditional SWOT analysis
Internal origin
(attributes of the organization)
External origin
(attributes of the environment)
Helpful
to achieving the objective
Harmful
to achieving the objective
S W
O T
STRENGTH
WEAKNESS
THREAT
OPPORTUNITY
Strengths and weaknesses are internal conditions, factors, or attributes.
Opportunities and threats are external conditions, factors, or attributes
A SWOT analysis aims to identify the strengths and weaknesses of an organization, a project,
enterprise, concept etc. and its opportunities and threats in the environment. The strengths and
weaknesses are identified by an internal appraisal of the organization (or project, enterprise, concept
etc.) while the opportunities and threats are identified by an external appraisal. The internal
assessment examines all aspects of the organization (or project, enterprise, concept) covering, for
example, personnel, facilities, location, products and production, services, in order to identify the
organization’s strengths and weaknesses. ‘The external evaluation scans the political, economic,
social, technological, and competitive environment with a view to identifying opportunities and
threats’ (Dyson, 2004:632).
42
4. Study Area
4.1.
Geographical space
4.1.1. Location
The state San Luis Potosi is located in the center of Mexico. Tercera Chica is a district located in the
north of the city San Luis Potosi which is the capital of a Mexican state called San Luis Potosi as well
(Figure 4.1.1); the municipality of San Luis Potosi is located between 22: 09' 10'' north latitude and
100: 58' 38'' west longitude.
Figure 4.1.1: Map of Mexico, map of San Luis Potosi and map of Tercera Chica
Source: CTREIG, 2002 and INEGI, 2002
The city’s area is 1,362.38 km2, which are 2.20% of state’s surface and is located 1,860m above sea
level. The city’s geographical limits are following municipalities: to north Moctezuma and Villa de
Arista, to the south Villa de Arriaga and Villa de Reyes, to the east Cerro de San Pedro, Soledad de
Graciano Sánchez, Villa Hidalgo and Zaragoza and to the west Ahualulco, Mexquitic de Carmona, and
Villa de Arriaga.
4.1.2. Climate
According to INEGI (2003) the climate of the region ranges from dry to very dry, the average annual
temperature is 16:- 18:C and the annual average rainfalls are 300- 400 mm (Table 4.1.2).
43
Köppen’s Climate modified by Garcia (INEGI, 2003) is BWkw which is characterized by rains of
summer with a percentage of winter rainfall from 5 to 10.2% and hot summers.
Wind: San Luis Potosi’s prevailing wind direction in 2010 was South West (INIFAP, 2010).
Table 4.1.1: Average monthly temperature and precipitation in
of San Luis Potosi
Annual Average
Temperature
17.3:C
Annual precipitation
Rainfall
386.4mm
Source: INEGI, 2003
Figure 4.1.2: Climate diagram of San Luis Potosi
35,0
30,0
25,0
20,0
15,0
10,0
5,0
0,0
Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
70,0
65,0
60,0
55,0
50,0
45,0
40,0
35,0
30,0
25,0
20,0
15,0
10,0
5,0
0,0
Temperature 13,0 14,5 17,2 19,7 20,8 20,3 19,1 19,1 18,3 17,0 15,3 13,4
Rainfall
13,4 7,1
6,7 21,3 36,6 68,5 63,1 57,4 60,4 29,7 12,1 10,1
Source: INEGI, 2003
4.1.3. Geology and edaphology
The geology is characterized by sedimentary rock soils Q(s) from the quaternary period of the
Cenozoic Era (INEGI, 2003).
4.1.4. Soil
The main soils of the area are haplic xerosol soil and luvic feozem soil of medium texture Xh+Hl/2
(INEGI, 2003).
4.1.5. Hydrology
According to INEGI (2003) there are no important surface water and groundwater sources in the
surrounding areas of Tercera Chica.
44
4.1.6. Vegetation
Because Tercera Chica is nowadays an urban settlement, native vegetation is not commonly
presented; however, it is possible to see some native trees and small bushes in some places, close to
the brick producing sites and the railroad tracks; and even small crops which people use to produce
animal food are present. Native vegetation includes Prosopis sp. and cactus like Opuntia sp., Larrea
tridentata, among others.
4.1.7. Urban structure (segregation, transport, etc.)
Tercera Chica is an outcast neighborhood located at the north edge of the city, in this way Tercera
Chica is one of the most segregated settlements of San Luis Potosi, there are a lot of streets and
small corridors without pavement and some areas look more like rural than urban landscapes, some
places are used to dispose garbage and construction waste, or in other cases parts of the land are
used for crop growing and livestock breeding such as horses, pigs, chicken, etc.
Public transportation is limited to one or two bus routes and local services are not very well
developed, small stores are the main way to acquire commodities.
45
4.2.
Cultural space
4.2.1. Population
According to the 2005 census the population of the Tercera Chica district accounts of 2991 habitants
which is 0.44% of the total urban population of San Luis Potosi (685,934) (730,950). The district is
considered as highly populated. The distribution of gender is relatively consistent, without any
superior tendencies (Figure 4.2.2). The average household size is 5.5 persons with the total number
of households being 592 (INEGI, 2005).
Figure 4.2.1: Total population and gender distribution in Tercera Chica
3500
Population
3000
2991
2500
2000
1500
1000
1500
1491
Male
Female
500
0
Total population
Source: INEGI, 2005
In 2005, 58% of the total population belonged to the economically productive group of 15 – 65 years.
The group of children between the ages of 1 – 14 years has a percentage of 38%. The percentage of
elderly people above 65 years of age is 4% of the total population (Figure 4.2.3) (INEGI, 2005).
Figure 4.2.2: Population and age group in Tercera Chica
3500
Population
3000
2500
2991
2000
1500
1738
1000
500
494
640
119
0
Total
Population Population Population Population
population from 0 to 5 from 6 to 14 from 15 to
from 65
years old
years old 64 years old years and
older
Source: INEGI, 2005
Most of the people living in Tercera Chica were born there (92%). There is no essential increase of
population of the entity due to migration of people from other places (INEGI, 2005).
46
In 2005, 56% (1638) of the total population of Tercera Chica was not entitled to health services
(Figure 4.2.4). The 42% of the total population of the district who were entitled to health care had
mainly the IMSS20 health care (1139 or 91%) (INEGI, 2005).
Figure 4.2.3: Health service of the population in Tercera Chica
2%
Population
entitled to health
services
42%
Population not
entitled to health
services
56%
Not specified
Source: INEGI, 2005
4.2.2. Education
In 2005, INEGI reported that 57% of the total population, 15 years and older, in Tercera Chica is
literate (Figure 4.2.5) of which 52% are women. Six percent of the total population of age 15 and
older has no education, while 12% have incomplete primary education. Fifteen percent of the total
population of age 15 and older finished the primary school. Nineteen percent of the total population
older than 15 years has finished a technical profession. Fifteen percent of the total population older
than 15 years has finished the secondary school or the university-entrance diploma. Just under 4% of
the total population older than 15 years has finished a higher education (university or qualified
career) (INEGI, 2005).
Figure 4.2.4: Educational level of population of the age 15 years older in Tercera Chica
Population of age 15 and older
2000
1857
1800
Total population of age 15 and older
1709
Literate
1600
No education
1400
Incomplete primary education
1200
Complete primary education
1000
800
600
400
200
Secondary school or technical
studies
Upper secondary or higher education
571
359
172
449
289
154
Upper secondary education
92
0
Source: INEGI, 2005
20
IMSS is a governmental organization for health care for the working class.
47
Higher education
4.2.3. Dwellings
In the year 2005 private dwellings of a total of 538 were reported in Tercera Chica most of these
dwellings show stabile structures, constructed with materials like brick and concrete (between 92.5 –
94%). Light roof structures and walls constructed of light, natural or other precarious materials are
found in 5 – 6.5% of the dwellings (Figure 4.2.6) (INEGI, 2005).
Figure 4.2.5: Construction materials of private dwelling in Tercera Chica
600
505
501
Private dwellings
500
498
Roofs of light, natural or
precarious material
400
Roof of concrete tile, brick or
with beams
300
Walls of light, natural or
precarious material
200
Walls of brick, block, stone,
quarry, cement, concrete
100
Floor of cement tile, wood,
or other coating
35
29
0
Source: INEGI, 2005
Most of the dwellings in Tercera Chica count with public services such as drainage, electric energy,
and piped water (Figure 4.2.7). Just 2 – 6% of the dwellings are not connected to the public drainage
network. Also should be mentioned that in most of the dwellings gas is used for cooking (95%)
(INEGI, 2005).
Figure 4.2.6: Infrastructure and public services of the private dwellings in Tercera Chica
600
513
500
527
Using gas for cooking
493
Private dwellings
433
400
With drainage connected to
public grid
Connected to septic tank,
crack, river or sea
300
Without drainage
200
Connected to electric grid
100
10
Access to potable water
32
0
Source: INEGI, 2005
Of the 538 private dwellings 72% are inhabited by the owners and 18% of the dwellings are rented
(Figure 4.2.8) (INEGI, 2005).
48
Figure 4.2.7: Dwelling ownership in Tercera Chica
600
538
Private dwellings
500
Total of private
dwellings
400
387
Self inhabited by
owner
300
Rented
200
100
97
0
Source: INEGI, 2005
4.2.4. Economy
According to INEGI (2005) 34.5% of the total population above 12 years of age is economically
inactive in the Tercera Chica (Figure 4.2.9). In 2005 a total of 1022 person older than 12 years were
economically active.
Figure 4.2.8: Population of age 12 and older economically inactive in Tercera Chica
1200
1000
800
1032
600
725
400
200
307
0
Population
economicall
inactive
Male
Female
Source: INEGI, 2005
Of the 1032 economically inactive persons 486 above 12 years of age are dedicated to domestic work
of which 99% are female.
Of the 1022 economically active persons 46% are employed in the secondary sector (471) and 50% in
the tertiary sector (510) and 4% are not specified (33). In the secondary sector 76% are among the
male population and 31% in the tertiary sector are male (INEGI, 2005).
Of the 1022 employed population 68% are employees and laborer, 5% as day laborer and unskilled
laborer of which 63% affiliates to the male population, 11% receive less than the monthly minimum
wage of which 61% belong to the male population (INEGI, 2005). The minimum wage per day in the
49
year 2005 was 44.05 MXN for the geographical region “c” 21 (Comisión Nacional de los Salarios, 2005)
which would mean that the monthly minimum wage is 1,321.50 MXN (30 days). 2% of the 1022
employed population in Tercera Chica does not receive incomes, of these 2% employed population
that does not receive income 41% are among the male population. For 12% of the employed
population no specifications indicating their labor agreement were available (Figure 4.2.10).
According to INEGI (2005) 188 persons were self-employed in Tercera Chica of which 76% were
among the male population.
Figure 4.2.9: Labor agreement of the employed population in Tercera Chica
Labor agreement
80%
Population working as
employees or laborers
70%
69%
60%
Population employed as day
laborer or unskilled laborer
50%
40%
Employed population
receiving less than the
monthly minimum wage
30%
Employed population that
does not receives incomes
20%
10%
5%
11%
12%
2%
Not specified
0%
Source: INEGI, 2005
21
Comisión Nacional de los Salarios sets the minimum wage per day. For the year 2010 the minimum wage per
day amounts to $54.47 for the geographical region “b” (Comisión Nacional de los Salarios, 2010).
50
4.3.
Mechanisms to protect the environment in Mexico
Mexico has developed a set of actions to mitigate climate change, although the government is not
yet able to quantify all of them accurately. During the nineties, the Mexican economy grew under
cleaner production patterns than in the past, and established inter-agency mechanisms that
contribute to the objectives of the United Nations framework convention on climate change,
avoiding significant emission quantities of greenhouse gases (INE, 1998).
The pollution control efforts in Mexico as in other developing countries have traditionally focused on
large industrial sources, although informal firms create severe environmental problems. Informal
firms are staying beyond conventional regulatory instruments given the fact that it is difficult to
monitor them, since they are small, numerous and (by definition) have few preexisting ties to the
state. Also such firms have few economical resources to invest in pollution control (Blackman, 2000).
The literature mentions that anthropogenic atmospheric contaminant emissions are divided into two
sources: stationary and mobile sources; there are three types of stationary sources: 1. point sources,
2. area sources and 3. natural sources (Bravo and Sosa, n.d.).
Point sources include large industrial activities which can be relative easy monitored, area sources
are those which cannot be included in an effective way into the point source inventory because they
are too dispersed, small, and numerous. Informal brick kilns belong to the area sources which is the
main reason why it is difficult to accurately measure the amount of their emissions (Radian
International, 1997).
However, there exist some methodologies to obtain rough estimations based on aspects like activity
data and emission factors, which relate the amount of emitted contaminants with the units of
activity (Radian International, 1997). According to the “Emissions inventory program in Mexico”
(Radian International, 1997) the most important aspects which have to be considered in emissions
estimation for brick production are: determine the amount and type of each fuel used in the study
area, number of kilns located in the study area, emission factor by fuel type and bricks production
capacity from each kiln.
However, this research could not consider the exact determination of fuel types and their amounts
used in Tercera Chica for two reasons: 1. Fuel mainly used in Tercera Chica is residential waste which
contains various different materials such as plastics, paper, wood, textiles etc.; taking into account
the high amounts of this heterogeneous fuel necessary for one kiln (up to 7m3) the working force of
one investigator wasn’t enough to separate and weigh the fuel’s elements. 2. The time intensive
determination would have interfered with the working flow of the brick producers as they buy the
fuel shortly before firing the kiln.
51
4.3.1. Environmental policies for traditional brick industry in Mexico
As in other developing countries Mexico has not been able to regulate the brick production’s
atmospheric emissions, according to Blackman (2006:72) “efforts to control pollution from
traditional kilns in Mexico have not been coordinated at the national level”; rather, individual states
have implemented a variety of strategies (Table 4.3.1).
During the 1990’s the Mexican government established official standards (NOMs, Appendix 2) for air
quality but as it turned out these standards are difficult to apply to the informal sector such as the
informal brick production which generates very low incomes and therefore cannot invest in
mitigation of emissions (Blackman, 2000).
According to the literature, efforts from some individual state governments of Mexico have been
more effective than the national official standards. State level strategies are focusing more on public
and private sector initiatives, clean technology changes, subsidies for relocation, process
standardization, among others (Blackman, 2000).
Table 4.3.1 resumes governmental efforts from four different states governments to regulate air
pollution and prevent harm to human health caused by informal brick production which can be
considered to be applicable in Tercera Chica’s informal brick production.
Table 4.3.1: Implemented policies of four Mexican state governments regulating air pollution of informal brick
industry.
Cd. Juarez
Saltillo
Zacatecas
Torreon
 Private-sector-led
 Public-sector-led
 Public-sector-led
 Public-sector-led
initiative with publicinitiative
initiative
initiative
sector cooperation
 Initial focus on clean
 Clean technological
 Clean technological
 Focus on clean
technological change
change
change
technological change
(conversion to
 (conversion to
 (conversion to
(conversion to
propane)
propane)
propane) plus
propane)
 Subsidies to fixed
 Subsidies to fixed
relocation
 Subsidies to fixed
adoption costs
adoption costs
 Promised subsidies to
adoption costs
 R&Da in energy Process standard
fixed relocation and
a
 R&D in energyefficient kilns
(ban on use of tires)
adoption costs
efficient kilns
 Process standards
underpinned by peer  Privately enforced
 Process standards
(ban on exclusive use  monitoring and
process standards
(ban of dirty fuels)
of tires) underpinned
registration
(ban on use of tires,
underpinned by peer
by peer monitoring
 Forced relocation of
firing limits)
monitoring
and registration
certain kilns
underpinned by peer
 Public education
 Subsidies to cleaner
 Boycott of bricks
monitoring
initiative
fuels (scrap wood)
fired with dirty fuels
 Boycott of bricks fired
from neighboring
with dirty fuels within
towns
Juarez
a
Research and development in pollution preventing technologies
Source: Blackman, 2006
52
5. Results and analysis
This chapter presents the findings of the fieldwork and their analysis. It is separated in four main
parts which are: results of surveys, kiln locations and conditions, non-participative observation of
brick production, and participative workshops. Each part has its own introduction, a short summary
of the applied methodology, and ends with a conclusion.
5.1. Results of surveys of brick producers in Tercera Chica, SLP
The following findings are results of the implemented questionnaires addressing traditional brick
producers who are members of Grupo Ladrilleros y Artesanos la Tercera Chcia A.C.
The interviewees are owners of brick kilns respectively managers of brick kilns. 25 (32%) of 76 brick
producers of the association participated in the survey. Two questionnaires were applied, the first
questionnaire focuses on the socio-economical conditions of brick producers in Tercera Chica and the
second questionnaire collects data concerning their brick production.
5.1.1. Results of socio-economical conditions of brick producers in Tercera Chica
The socio-economical conditions of brick producers can indicate which possibilities of technical
changes can be applied, and which factors are important for an improvement. Also the social
structure shows opportunities of the families of brick producers to socio-economical progress.
5.1.1.1.
Methodology
The data collection concerning the socio-economical conditions of the brick producers in Tercera
Chica was determined by semi-open surveys (Appendix 3). 25 brick producers participated in the
survey, these 25 participants representing 32% of the brick producers of the association “Ladrilleros y
Artesanos la Tercera Chica A.C.”, which is a rather low percentage for a survey. The survey is formed
by 30 questions related to personal data (age, education, family etc.), health condition, dwelling
conditions, and income of the brick producers. The questionnaires have been analyzed quantitative
with descriptive statistics using Office Excel.
5.1.1.2.
Results of socio-economical survey of brick producers in Tercera Chica
The 25 interviewees are all males; it is not common that there are brick producers who are female in
Tercera Chica, however other reports about brick producers of other Mexican states indicate that
there are also women who are brick producers (owners) respectively work in the brick production as
managers of brick kilns (Wilson, 2005: Ch.5 - 8). The average age of the interviewed brick producers
is 45 years (Figure 5.1.1) and almost all were born in the city of San Luis Potosi; just one brick
producer said that he is from the state of Guanajuato (south-west of SLP). Some even indicated that
there were born in Tercera Chica (53%). None of the interviewed brick producers is originally from
53
rural areas surrounding the city of San Luis Potosi whereas other reports state that brick producers
from other states of Mexico have often migrated from rural to urban areas (Romo Aguilar et al.,
2004).
Figure 5.1.1: Interviewed brick producers in Tercera Chica: Age groups
10
9
9
8
7
6
5
4
4
3
3
2
1
3
2
1
0
15-24
25-34
35-44
45-54
55-64
<65
Age group
Forty percent finished and visited the secondary school and one brick producer visited a higher
school (Figure 5.1.2); furthermore all brick producers who participated in the survey can read and
write. That illiteracy during the survey was not documented could be related to the fact that just
brick makers with school experience have participated, which leads to the assumption that the
participants have visited schools because it is easier accessible in urban areas where compulsory
schooling and educational offers exist, than in rural areas. Whereas in Ciudad Juarez approximately a
quarter of the brick producers are illiterate and in many cases have a migrant background, coming
from rural areas (See Chapter 2.2.1).
Figure 5.1.2: Educational level of brick producers in Tercera Chica
45%
40%
40%
35%
30%
25%
28%
20%
15%
10%
16%
5%
4%
0%
Incomplete
Complete
Secondray
Upper school (3
primary school primary school (6 school (3 years)
years)
years)
54
Even though 47% explained that they have chronic diseases (embolism, arthritis, diabetes, asthma,
hypertension, flu, high blood pressure, and epilepsy) just 14% of the participants indicated that their
health is bad and 27% and 59% said that their health is good respectively regular. Nobody indicated
diseases such as cancer, but it can be assumed that there is a high tendency of cancer and other
diseases among the brick producers. Investigators of the UASLP are currently implementing a study
about the health conditions of the brick producing community in Tercera Chica. 14% of the
interviewed do not count with health insurance. The majority (76%) has the health insurance
“Popular”22 and 10% have the IMSS insurance.
The family status of all participants shows that all interviewees are married and have children, living
together with the family (wife, children and 32% also have grandchildren). The average number of
persons in a household is 6; a little above the average household size of Tercera Chica (5.5); while the
maximum is 12 persons per household and the minimum is 2. The size of the dwellings has an
average of 5 rooms per dwelling including bedrooms, living room, dining room and bathroom and 3
persons per bedroom (Figure 5.1.3), which indicates that the families live together in tight spaces.
Figure 5.1.3: Dwelling and household of brick producer families in Tercera Chica
25
20
15
12
11
Average
10
Minimum
6
5
5
5
3
0
Maximum
2
Rooms per
dwelling
1,4
2
1
6
2
Persons per Bedrooms per Persons per
room
dwelling
houshold
Seventy six percent of the participants live in Tercera Chica; the rest (24%) have their homes in
nearby districts (Las Palmas, Los Limones, Pedroza Tercera Grande). Sixty four percent of the
interviewed brick producers are owners of the houses they are living in, while 14% are renting a
house and 23% are borrowing the house of family members. Most of the dwellings are connected to
22
The insurance “Popular” is part of the Social Health Protection System, which seeks to provide health care
coverage through public insurance and voluntary for poor people who do not have jobs or are self-employed
and are not entitled to any social security institution (Seguro Popular, 2009).
55
public services, given that Tercera Chica is located in the urban area of San Luis Potosi (Figure 5.1.4).
The 17% of the participants not counting with access to piped water receive water from wells.
Figure 5.1.4: Access of the brick producers’ dwellings to public services in Tercera Chica
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
100%
89%
83%
61%
Water
Electricity
Gas
Drainage
Public Service (including gas*)
*Gas needed for cooking and hot water is not a public service, but gas is sold
to households by private firms.
All of their dwellings are made of bricks (58%) or a combination of bricks with other construction
materials such as adobes (16%), concrete (32%), and corrugated metal sheets (10%).
Other indicators describing the economical condition among the brick producers are their means of
transportation. Most of the brick producers (55%) are using a bicycle as principal mean of
transportation and 15% move by food. Just one person has a car and the rest is using mainly public
transportation. Fifteen percent are using other means of transportation such as motorcycles (Figure
5.1.5).
Figure 5.1.5: Means of transportation used by brick producers in Tercera Chica
60%
55%
50%
40%
30%
20%
20%
10%
5%
15%
15%
By food
Other
5%
0%
Car
Public
Organized
transportation transportation
Bicycle
Transportation
56
The average time span of the interviewees working as brick producers is 27 years (maximum 50 years
and minimum 8 years). According to the interviewed brick producers the traditional brick industry
exists since 1960 in San Luis Potosi. Some interviewees form already the third generation of brick
producers in their family. Fifty six percent said that their children are working in the brick industry.
Three brick producers indicated that their under aged children (age 12, 13 and 16 years old)
participate in the work of the traditional brick production.
Working cloth is not used among the brick producers and their workers, 100% indicated that they
have no working cloth.
Thirty two percent of the brick producers explained that their wives are economically active and 36%
reported that the children who live in their homes are as well contributing to the income of the
family. The average monthly income of the participants’ households amounts 5140 MXN (Mexican
Peso). Twelve percent of the brick producers indicated that part of the family’s monthly income
consists of scholarships issued to their children, who live in the household. One person said that the
family has taken credits from a bank; while 84% do not receive any financial benefits (e.g.
INFONAVIT, FONACOT, bonus, scholarships, credits, or others).
The average monthly income of the interviewed brick producers is 3109 MXN (=250 USD) per month,
which lays clearly above the by FEMAP mentioned (quoted in Blackman & Bannister) monthly profit
of 100 USD a brick producers generates in Ciudad Juarez. The difference could be explained by the
fact that the FEMAP source is older than ten years, and that the brick producers in Ciudad Juarez
employ an average of 6 workers a day for their production, while the brick producers in Tercera Chica
contract only an average of 4 workers.
5.1.1.3.
Conclusion
The socio-economical conditions of the 25 participating brick producers of Tercera Chica indicate that
the economical conditions are better than Ciudad Juarez, given that the brick producer have a higher
monthly average income (250 USD) compared to the reported monthly income of the brick
producers in Ciudad Juarez (100 USD). The brick producers of Tercera Chica work all year long in the
brick production and do not depended on the conduction of other economical activities as it is typical
in other regions (Wilson, 2005; PRAL & Ministerio de la Producción, 2008).
Nevertheless the socio-economical conditions of the brick producers in Tercera Chica are poor
according to the results of the applied survey. The average family income of 5140 MXN (= 420 USD)
per month shows that in an average household of 6 persons, 856 MXN (70 USD) is monthly available
per person. The low income of the family explains that 67% of the participants have the “Popular”
health insurance and 14% even have no health insurance at all. The “Popular” insurance is mainly
57
used by people living in marginal conditions, rural and indigenous areas, or people who are not
employed or employed and have no access to health services in other institutions. As already
indicated 56% of the population of Tercera Chica was not entitled to health insurances in 2005 and
56% have the IMSS health insurance.
The education level of the brick producers is higher than the educational level in Ciudad Juarez
(average of three school years among brick producers). However the fact that just 25 brick producers
participated in the survey, while 40 brick producers were present on the day of the hand out of the
survey, could indicate that the rest (15 persons) of the invited brick producers did not fill out the
survey because of problems understanding and/or reading the survey. Again 43% of the population
in Tercera Chica is illiterate (Chapter 4.2.2.), so it can be assumed that there is illiteracy among the
brick producers. Astonishing is that the majority of the participants (40%) visited the secondary
school while INEGI (2005) states that only 15% of Tercera Chicas’s total population finished the
secondary school, which could mean that many of the brick producers are represented by this part of
the population of the Tercera Chica.
The dwellings of the brick producers are made of stabile materials (concrete, bricks and adobe)
which is common in Tercera Chica where in 2005 just 35 dwellings were made out of light materials
(Chapter 4.2.3.). And most of the brick producers (64%) are owners of their home. Nevertheless the
dwellings are relatively small (3 persons per bedroom).
Minors are early introduced to the work in brick production, and most of the children are continuing
later to work in the same sector. Given that most of the brick producers know that child labor is
illegal23 they probably do not admit that their children or grandchildren participate in this labor
intensive production process. Anyhow during the field work of this investigation, four cases of child
labor were observed.
The results of the survey lead to the conclusion that the socio-economical conditions among brick
producers are not the worst in the district of Tercera Chica but still are poor: low economical income,
child labor, small dwellings, no health insurance or only basic health insurance, indicate poor
conditions. In addition an important observation is that informal brick production is a family business
which is passed on from generation to generation (some brick producers in Tercera Chica already
form the third generation of brick producers). As mentioned above children are involved at a young
23
According to the Constitution of the United Mexican States and the Federal Labor Law (La Ley Federal del
Trabajo, Artículo 22) minors younger than fourteen years are not allowed to work at all. Minors of fourteen to
sixteen years are only allowed to work if they have completed their obligatory education. Nevertheless
corresponding authorities can make exceptions if the work of minors from fourteen to sixteen years is
interlinked with their studies (e.g. internships).
58
age learning how to produce bricks which supports the family economically in short term but does
not support the academic progress of the children in the long term. Therefore the informal brick
production industry can be seen as a vicious circle: low margins force brick producers to cut costs in
order to continue to support their families economically. This is accomplished by involving minor
family members in the production process who end up later working as brick producers themselves.
5.1.2. Results of survey about brick industry in Tercera Chica
This part aims to give a general review on the brick industry in Tercera Chica (e.g. type of kilns in
use), the production costs of bricks, cooperation, and opinions about relocation. In the Appendix 4 is
a calculation of the total expenditure per brick production, the gross income and net income.
5.1.2.1.
Methodology
To determine the primary data of the traditional brick industry in Tercera Chica a semi-open survey
with 46 questions (Appendix 3) related to the kilns, cost of brick production, existing production
sites, brick demand, labor data, implemented improvements and relocation was carried out. Forty
brick producers of the association Ladrilleros y Artesanos la Tercera Chica A.C. were present when
the survey was handed out. Only 25 brick producers filled out the survey. These 25 brick producers
represent 33% of the association’s members. The data was analyzed using descriptive statistics in
Microsoft Excel.
5.1.2.2.
Kiln industry in Tercera Chica
Some of the brick producers are not owners of a kiln; 20% of the interviewees explained that they
rent a kiln for an average amount (paid in bricks) of 660 bricks respectively 580 MXN (calculated with
the average price of a brick).
One (4%) of the interviewed brick producers has three brick kilns, three (12%) have two kilns, and the
rest have one brick kiln. Nineteen percent of the interviewed explained that they owned more brick
kilns in the past, but in contrast to other cities (e.g. Ciudad Juarez, Romo Aguliar et al., 2004) the
brick producers in Tercera Chica did not lose them due to financial reasons, but gave them to their
sons.
The average kiln age is 20 years (the oldest kiln is 45 years and newest is 5 years old). Twenty three
percent have their brick kiln are located on the same property as the dwelling of the owner. The
average firing of a kiln takes 17 hours. The duration of the firing depends on the condition of the
brick kiln and its size. It could be assumed that the kiln age indicates the effectiveness of a kiln; the
older the kiln the worse its condition which results in longer firing times; the collected data disproves
this assumption: the minimum duration of a firing process is 12 hours (kiln age: 10, 15, 25, 30 years)
59
the maximum duration is 30 hours (kiln age: 10 years); the brick kiln of 45 years has an average firing
time of 20 hours while the kiln of 5 years has a average firing duration of 18 hours. The age of a brick
kiln does not indicate the condition of a kiln (leaks etc.) (Table 5.1.1).
Table 5.1.1: Comparison kiln age with duration of firing process
Kiln age (years)
Duration of firing
process (h)
5.1.2.3.
45 15 10 20 20 15 35 25 10 20 25 10 15 15
5
23 12 20 28 30 16 20
20 12 12 18 19 28 22 25 12 14 15 30 12 16 18 18 16 14 24 18 12 13
Fuels
The most common used fuels for the firing process in Tercera Chica are: wood, used oil, tires,
plastics, sawdust, and other wastes (paper, shoes, waste fabric etc.). Figure 5.1.6 shows that wood
(84%) is mostly used among the interviewees, followed by tires (56%). Wood reaches such a high
percentage because almost all brick producers use it to ignite other fuels given that brick producers
do not exclusively use one fuel, but use different fuels during the firing process24. Gas (propane,
natural gas) is not used at all because of its high price.
Figure 5.1.6: Used fuels for firing process among participants of the survey
90%
80%
84%
70%
60%
56%
50%
40%
40%
30%
36%
20%
10%
16%
0%
16%
0%
Wood
Gas
Used oil
Tires
Plastics
Sawdust
Others
The average amount of the fuels is illustrated in the Table 5.1.2. The amount of the fuels used varies
significantly, for instance the maximum amount of used tires is 150 pieces per firing while the
minimum is 5 tires. The same is observed with the amount of used oil: maximum amount reported
was 1000 liters/firing (the brick producer uses exclusively used oil) and a minimum of 100 liter/firing
(the brick producer uses oil mainly for ignition of the fire). The amount of fuels varies according to
24
It was reported that one brick producer uses just tires for the firing process, but this brick producer did not
participate in the survey.
60
the capacity of the different kilns, type, number of different fuels used, and the capacity of the
workers to manage the kiln.
Table 5.1.2: Amounts of fuels used per firing among participants of the survey
Fuel
Unite
Wood
Tons
Minimum amount
5
4
6
Used oil
Liter
100
425
1000
Tires
Piece
5
52
150
Plastics
Tons
1
51
200
Sawdust
Tons
1
5
9
Other waste
5.1.2.4.
Average amount
Maximum amount
No specification
Brick production
The brick producers stated in the survey that they produce mainly four different types of bricks:
cuña, cuadrado, bovedilla, caguamo (Figure). All of the interviewed brick producers produce the cuña
brick, 60% produce also the cuadrado brick, 36% manufacture caguama bricks and 12% also bovedilla
bricks. The average prices per brick type are shown in Table 5.1.3.
Table 5.1.3: Average price per brick (MXN)
Cuña
Cuadrado
Caguamo
Bovedilla
$0,88
$0,94
$1,27
$1,20
The frequency of firings varies among the brick producers between 1-3 firings per month: 38% of the
interviewed brick producers accomplish one firing/month, 42% accomplish two firings/month and
21% accomplish three firings/month. The average amount of bricks produced per kiln in one firing is
approximately 13.000 bricks (Figure 5.1.7).
Figure 5.1.7: Minimum, average and maximum number of brick
production per kiln and firing in Tercera Chica
140000
120000
54000
100000
Maximum
80000
Average
36000
60000
45000
40000
20000
0
17000
28700
12889
8000
16000
1 firing
2 firings
61
30000
3 firings
Minimum
The Figure 5.1.8 shows the approximately average number of bricks produced per month throughout
a year in relation to the monthly rainfall in SLP. The production depends on the climate; during the
dry month (Oct.-May) the production is higher and decreases with the increase of rainfalls (Jun.Sep.). Reason for that is that bricks cannot be dried in the sun during the rainy months because none
of brick producers has a roofed area where crude bricks could dry protected from rain. The unstable
production of bricks leads to losses of income which make the family of brick producers more
vulnerable to poverty.
Figure 5.1.8: Average number of bricks produced per month in Tercera Chica and
average rainfalls per month in San Luis Potosi
25000
70,0
65,0
24500
60,0
55,0
24000
50,0
45,0
23500
40,0
35,0
23000
30,0
25,0
22500
20,0
15,0
22000
10,0
5,0
21500
Bricks
Jan
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
0,0
22875 23417 24792 24708 24042 23042 23458 23000 22708 23792 23292 24458
Rainfall (mm) 13,4
5.1.2.5.
Feb
7,1
6,7
21,3
36,6
68,5
63,1
57,4
60,4
29,7
12,1
10,1
Labor conditions of brick workers
According to the results of the survey a brick producer employs an average of 4 workers for the brick
production. The work of the production process in which the workers are engaged is described in
Chapter 5.2. For one brick production (1 firing/per month) the brick producer employs the workers
averagely for 5 days a month. The workers usually work for different brick producers during the
month. The average working hours per day is 10 hours; but 48% of the manufacturing brick industries
have an 8 hour working day, while 16% say they do not have a fixed schedule of hours per day
(Figure 5.1.9).
62
Figure 5.1.9: Participants working hours per day in the brick production of Tercera Chica
60%
50%
48%
40%
30%
20%
20%
16%
10%
16%
0%
0%
8 hours
8-10 hours
10-12 hours
> 12 hours
Variable
Most brick producers (78%) contract different workers on a daily basis (Figure 5.1.10) which causes
an often change of the workers. Participants lament that due to often changing personnel which has
to get acquainted with the kiln a high loss of bricks is caused by over or under firing.
Seventeen percent work with permanent staff. The advantage for the workers are a constant income
and for the owners a staff which is familiar with the kiln. Nine percent of the brick producers work
mainly with family members.
Figure 5.1.10: Type of employment among participants, Tercera Chica
9%
17%
Permanent
Dayly basis
Family members
78%
63
5.1.3. Production costs of bricks
5.1.3.1.
Fuels
Most of the fuels are obtained illegally from the waste landfill of SLP; sawdust is collected and bought
from carpentries, and used oil is collect and bought from mechanical workshops; which indicates that
the brick producers are creating synergies with other sectors to obtain fuels for the firing of the
bricks. The average expenses per fuel illustrated in Table 5.1.4 show that the most economic fuels
are tires and plastics. Wood and used oil cost more than twice as much as tires.
Table 5.1.4: Average price per fuel
Wood
Used oil
Tires
Fuel
Plastics
Others
Unit
Kg
Liter
Piece
Kg
Kg
Mexican Pesos
311
20
44
383
629
5.1.3.2.
Raw brick material
For the production of bricks following raw materials are needed: soil, additives, clay, and water. The
average expenditure for the materials is 2900 MXN, in which the soil is the most expensive material
(Figure 5.1.11). Some of the brick producers do not pay for water, given that they have dug wells on
their property.
Figure 5.1.11: Average expenditure (Mexican pesos) per raw brick
material per brick production in Tercera Chica
$1.800
$1.600
$1.669
$1.400
$1.200
$1.000
$800
$600
$400
$200
$417
$450
Additives
Clay
$364
$0
Soil
5.1.3.3.
Water
Workforce
According to the brick producers the average payment per day/worker is 194 MXN, the minimum
wage of a worker is 100 MXN and the maximum is 250 MXN. This range of income is clearly above
the Mexican minimum wage per day of 54.47 MXN (2010 for zone “C” to which the state SLP
belongs) (CONSAMI, 2010). Nevertheless it should be mention that even permanent staff is not
64
working 30 days per month because 2 firings per month create only approximately 10-14 days of
work.
To receive more accurate data on the income and conditions of the brick workers, a further
investigation is needed.
5.1.4. Cooperative
All interviewed brick producers are members of a cooperative called Ladrilleros y Artesanos la
Tercera Chica A.C. which was legally founded in 2004 (however some members mentioned that the
group began to meet in 2000). When asked why they are members of this association brick
producers stated that they share same or similar economic, social, marginalization, health, and brick
production problems which they want to resolve together. Also they feel more secure to confront
governmental politics concerning their brick production.
None of the members is part of a political party. According to the interviewees they do not join
political parties because they distrust them. The brick producers conceive the government as a
negative element that wants to eliminate their jobs rather than organize and offer advices and/or
help.
It is important to mention that brick producer trust more in universities, researchers and students
than in the government, because these, according to their experiences, have achieved more positive
progress.
5.1.5. Relocation
Eighty percent of participants accept relocation as an option to implement changes to their
production process; 20% gave no answer. Those open to a relocation project stated that in order to
accept relocation certain conditions must be fulfilled which are:

Well chosen terrain with clear tenure that allows them to stay for as long as possible; fearing
future settlements close to the chosen terrain could force them to move again.

Terrain has to be big enough for all brick producers.

Not too far away from their homes and accessible with public transportation.

Close to sources of raw material and fuels.

Sufficient infrastructure (water and electricity).
65
5.1.6. Governmental support
According to the results of the survey 50% of the participating brick producers are not aware of
attempted governmental support actions, 24% know about the governmental support actions, and
24% of the participants gave no answer to this question.
From those who know about governmental support actions 52% believe that the results were bad,
8% think that there were no changes, 4% couldn’t estimate the results, 36% gave no answer, and
none of the interviewees believes that the results were good.
Due to the fact that half of the brick producers are not aware of any attempted governmental
support actions it can be assumed that there have been communication problems between the state
government, trying to implement mentioned programs (relocation program; MK2), and the brick
producers.
The relocation program which was planned by the local government was canceled this year by the
new local government. The brick producers stated that with the change of the government they are
back at the beginning and have to start over again in order to establish communication with newly
elected authorities.
5.1.7. Implemented improvements by brick producers
Seventy six percent of the brick producers indicated that they have intended respectively
implemented improvements in one of the following areas: kiln (closing leaks and gaps), fuels, firing,
and applying alternative materials. One hundred percent say that the area of capacity building of
themselves and their workers was never implemented, but would be urgently needed to make
efficient changes in the industry (reduction of contamination, preventing heat losses etc.).
Due to the lack of governmental assistance the brick producers are searching on their own for
improvements applicable to their production process (e.g. cleaner production tools). Their
opportunities are limited because of limited financial possibilities.
Some actions they took to find improvements are:

Better insulation of their kilns

Use of recycled oil

Research electrical kilns

Mechanization of the mixing production step
66
Passivity towards changes and improvements cannot be found among the brick producers. Hope still
exists that the government could support a change, but the trust in politicians is extremely low,
because of the frequent disappointments.
5.1.8. Conclusion
The results show that the informal brick sector is a labor intensive, low technology activity generating
low profits. The used fuels (wood, used oil, tires, plastics, and waste) emit pollutants (Chapter 2.1.1.)
during the combustion. The participants mentioned in the socio-economical survey that they have
lung diseases, respiratory symptoms (e.g. asthma, coughing), and cardiac diseases which are
consequences of the work in the brick production (Chapter 2.1.2.).
Among brick producers the cooperative is conceived as an important instrument to address their
problems to the authorities which are generally distrusted. Therefore future governmental projects
like relocation programs have to consider the brick producers’ experience and knowledge throughout
the program in order to succeed. Generally the brick producers a willing to relocate their kilns but
only if no obstacle hinder their brick production. The brick producers’ statements concerning
relocation of their kilns draw a clear picture of issues that have to be addressed in the case of
implementation of a relocation program.
Despite the lack of governmental help brick producers search for enhancements for their production
process on their own. They have even intended to apply some enhancements with medium success
which is why they are searching institutions giving capacity building classes.
67
5.2. Kiln locations and conditions of Grupo Ladrilleros y Artesanos la Tercera Chica A.C.
According to brick producers there are an estimated total of 120 kilns in Tercera Chica. On two
occasions (30th of November and 2nd of December) accompanied by representatives of Grupo
Ladrilleros y Artesanos la Tercera Chica A.C. 57 kilns, which belong to members of the cooperative,
were located using a Global Positioning System- tracker (GPS-tracker). The reasons why only kilns
belonging to members of the cooperative were located are: the other brick producers were lacking
interest and difficulties in establishing contact.
5.2.1. Methodology
The geographical coordinates of 57 kilns located in Tercera Chica and owned by members of Grupo
Ladrilleros y Artesanos la Tercera Chica A.C. were collected via a Global Position System (GPS)
tracker. The geographical coordinates were aggregated to existing maps of SLP. Furthermore the
condition of each kiln was evaluated using a checklist with indicators (Very good, Good, Poor, Very
poor). Photos of all located kilns were taken (Appendix 5).
5.2.2. Results of kiln location and conditions
The cooperative Grupo Ladrilleros y Artesanos la Tercera Chica A.C. accounts of 76 members. Not
every member owns a kiln. Those members not owing a kiln are workers. A total of 45 members own
one kiln and 6 members own two kilns. This leads to the assumption that there are 25 members who
are not kiln owners.
The following table describes the conditions of the located kilns:
Table 5.2.1: Evaluation of brick kiln conditions in Tercera Chica
Condition
Very good
Good
Poor
Very poor
Description
No cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
Many cracks in kiln walls, kiln structure damaged
Kiln walls are severely damaged, supporting structure is applied
No.
5
18
20
13
56
%
9
32
36
23
100
39% of the kilns have rectangular geometry and 61% a quadratic geometry, which is more efficient as
explained in Chapter 2.3.1.4 about CP methods which recommend a quadratic geometry because it
has a smaller cooling area and therefore reduces heat losses. The Table 2.3.5 in Chapter 2.3.1.1 is
explained that a firing chamber beneath the ground level is more efficient than above the ground
level; the result of the evaluation of the kilns show that the majority (91%) of the kilns are equipped
with a firing chamber beneath the ground level.
68
The prevailing wind direction of San Luis Potosi as mentioned in Chapter 4.1.2. is South/West. As
figure 5.2.1 shows, only 7% (North/East and South/East) of the located kilns have a firing chamber
oriented in a 90° angle to the prevailing wind direction.
Figure 5.2.1: Relation of wind direction to firing chamber
35%
31%
30%
25%
20%
21%
17%
18%
15%
10%
6%
5%
1%
5%
1%
0%
The generated coordinates were aggregated to the map CTREIG (2002) and INEGI (2002) (Figure 5.2.2
and Figure 5.2.3) which indicates the location and conditions (Figure 5.2.2) of the brick kilns
according to the indicators of Table 5.2.1. Appendix 5 holds detailed data on location, names of the
owners, capacity, condition of the kilns, and photos. The age of each kiln was also of interest but
during the collection of the GPS data many kiln owners weren’t present and the majority of the
workers didn’t know the exact age of the kilns they were working with. Nevertheless the carried out
surveys presents the age of 25 kilns (see 5.1.).
The majority of the located kilns are within Tecera Chica limits. Nevertheless some are found outside
close to Tercera Chica. One kiln still is under construction. All 57 kilns have a total capacity of 841,500
bricks per firing. An average of two firings per month leads to a total monthly production capacity of
1,683,000 bricks.
69
Figure 5.2.2: Map of locations of kilns owned by members of Grupo Ladrilleros y Artesanos la Tercera Chica A.C.
in residential area of SLP
Source of map: CTREIG, 2002 and INEGI, 2002
70
Figure 5.2.3: Map of locations of kilns owned by members of Grupo Ladrilleros y Artesanos la Tercera Chica A.C.
and location of selling points of bricks
Source of map: CTREIG, 2002 and INEGI, 2002
71
5.2.3. Selling points of bricks
Main client for traditionally made bricks is the private residential construction sector. In private
residential construction usually an experienced mason is hired who selects a team of unskilled
workers. This mason is in charge of buying the required construction materials. Due to his experience
he has good contacts to brick producers and knows where to buy cheap construction materials like
traditionally made bricks from Tercera Chica. The mason organizes a truck and buys bricks from brick
producers in Tercera Chica directly.
This has changed over the last years. Nowadays almost all bricks are sold by middlemen who buy the
bricks in Tercera Chica and bring them to established selling points throughout the city where the
bricks are sold at higher prices (1.000 good quality bricks are sold at around 1.000 MXN) and brought
to the construction side by the same middlemen. In other words the middlemen offer transportation
as long as the construction site is located within city limits. This change has different reasons:
 The buying party doesn’t have to organize transportation.
 The buying party doesn’t have to enter Tercera Chica which is believed to be an area
with a high crime rate.
There are four major selling points (Figure 5.2.3) for traditional bricks throughout the city of San Luis
Potosi. They are all strategically well chosen meaning that they are near highways and
agglomerations of shops selling construction material, hard ware stores, cement distribution centers,
and market places.
The first visited selling point is located right next to the inner city highway exit ‘Avenida Falk’ close to
the San Luis football stadium. There are approximately 15 sellers who are all from Villa de Reyes a
small city 55 Km south of San Luis. They sell bricks at 1.1 MXN per piece. All the sellers in this selling
point agreed on this prize, which makes it nonnegotiable. This prize includes the transportation to
the construction site if it is located within city limits. However the sellers are either brick producers
themselves or just sellers. There is no sort of organization. Only regular traditional bricks with the
measures of 25 cm/12/5.5 are sold. No other types are available. The raw materials needed for their
production are found in Villa de Reyes itself. Their clients are almost always private persons.
The second is located in Topacio/Carretera D.F. next to a Moctezuma Cement distribution center.
There are about 25 sellers mainly from Villa de Reyes and only two from Tercera Chica. No brick
producer is selling at this selling point. Different types of bricks are sold. The traditional bricks
(25/12/5.5) are being sold for 1 MXN per piece. The ‘Cuadro’ a quadratic tile (22/22/1) is being sold
for 1.5 MXN. The prices include transportation to construction sites within city limits. There is
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supposed to be a form of organization but the interviewee couldn’t recall the name. Their clients are
mainly private persons.
The third selling point visited is located on the national highway to Rio Verde at Km 5. Nearby exists
an agglomeration of hard ware shops selling cement, tools, and paint. Only regular traditional bricks
(25/12/5.5) are being sold. The 15 sellers are from Villa de Reyes and are just sellers and not
producers. There is no organizational form. An average of 15.000 bricks is sold per seller per month.
If the bricks are not sold at the end of the day they are brought back to Villa de Reyes. Their clients
are mainly private persons.
The fourth selling point visited is located in Saucito which is an area known as the entrance to
Tercera Chica. This selling point is located along Carretera Federal 49 leading north to Zacatecas and
south to San Luis’ city center. Mainly traditional bricks (25/12/5.5) and frequently ‘Cuadros’
(22/22/1) are being sold. Current prices for traditional bricks are around 1 MXN per brick and for
‘Cuadros’ 1.5 MXN. Bricks sold here come mainly from brick producers of Tercera Chica. There is no
form of organization or cooperative between the sellers. Clients are mainly private persons. This
selling point seems more chaotic then any of the others due to a close by market place which attracts
lots of people.
5.2.4. Conclusion
The majority of the kilns are located in Tercera Chica however some are outside the urban area. Kiln
capacities range from 6.000 to 40.000 bricks. By looking at the kiln conditions (41% of the kilns are
either in good or very good condition and 59% are in either poor or very poor condition) one could
assume that the overall situation isn’t all that bad. But it is important to remember that the
traditional kiln (a.k.a. scotch kiln) design, which resembles all of the located kilns, is among the most
inefficient kiln types there are. In other words the 41% of the traditional kilns which are in good and
very good condition still are far more inefficient than for example the Vertical Shaft Brick Kiln (VSBK)
not to speak of the 59 % of traditional kilns which are in poor and very poor condition.
Bricks produced in Tercera Chica are mainly sold at the fourth selling point close to Tercera Chica.
The fact that brick producers sell their bricks for 650 - 750 MXN per thousand to intermediaries who
then sell them for 1,000 – 1,100 MXN per thousand to clients shows that higher margins for brick
producers are possible If they sold their bricks directly to the clients. The reason why brick producers
don’t sell their bricks directly to the clients is that waiting for clients is a time consuming and often
rough challenge due to high competition and low demands.
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5.3. Non-participative observation
The brick production process was observed to find out how the bricks is made and to know which
kind of pollutions are most likely emitted and to make suggestion for improvement within the scope
of cleaner production methods. In the following the brick making process is detailed documented
with indications of pollutions and suggestions to improve the manufacturing process. The suggested
improvements comprehend economical and/or environmental benefits.
5.3.1. Methodology
The documentation of the brick production process is the result of the non-participative observation
in the brick industry, photos and notes were taken of the brick making process. On four different
occasions the brick production process of a traditional brick maker, who is one of the representatives
of Grupo Ladrilleros y Artesanos la Tercera Chica, was accompanied and documented. His production
process was taken as an example for all of Tercera Chica because each brick producer basically
operates the same way.
The documented process has been analyzed using scientific literature about emitted contaminations
during the brick making process and CP-methods to improve the energy efficiency of the process as
recommendations.
5.3.2. Brick production processes
On four different occasions the brick production process of a traditional brick maker who is one of
the representatives of Grupo Ladrilleros y Artesanos la Tercera Chica was accompanied and
documented. His production process was taken as an example for all of Tercera Chica because each
brick producer basically operates the same way. The only kiln type used among members of the
cooperative is the traditional kiln. The only differences observed among brick producers were that
some prefer different fuels.
Figure 5.3.1: Panorama photos of a brick making area
74
The accompanied brick producer explained the following production steps while doing them: mixing,
molding, drying, loading the kiln, firing, unloading the kiln. Additional questions were asked by the
investigator. Photos were taken in order to draw a clearer picture of each production step. Focus was
put on costs and prices of each production step.
Previous production steps to mixing, which are extraction of soil and transportation of soil to the
brick production site were investigated later. Former and current extraction areas were visited.
The last production steps which are transporting fired bricks to selling points and selling were
documented at the final stage of the investigation.
On two other occasions’ informal brick producers in Los Cuarenta, Jalisco and Ciudad Juarez,
Chihuahua were visited. Due to the lack of time a detailed documentation like the one accomplished
in Tercera Chica wasn’t possible. Nevertheless a general overview was gained indicating that
production processes in all three locations are basically the same with on major exception, which are
the applied kiln types. In Tercera Chica the Clamp Kiln is used, whereas in Los Cuarenta the Scove kiln
is predominant and in Ciudad Juarez the visited production sites operate the Marquez Kiln (MK2).
The brick production process consists of clay and sand extraction, transportation of clay and sand,
clay preparation, mixing, forming or molding, drying, loading the oven, firing, cooling, unloading,
transportation/distribution (Table 5.3.1).
75
Table 5.3.1: Production process and impacts of traditional brick industry in Tercera Chica, SLP, Mexico
Steps
Production step
Time needed
By whom
Persons
Where
Emissions
Pollutants
1
Extracting clay and sands from ‘Banco de
Materiales’
< 1 hour
Distributor
1-2
Private and
public lots
Yes
Few PM, CO2if
machinery is used
2
Transporting clay and sands to Tercera
Chica
< 1 hour
Distributor
1-2
/
Yes
CO2
3
Mixing (Figure 5.3.2)
1-2 hours
Brick makers
1-2
3era Chica
No
Few PM
4
Molding (Figure 5.3.3)
1 day
Brick makers
1-2
3era Chica
No
None
5
Drying (Figure 5.3.4)
5-7 days
Brick makers
0
3era Chica
No
None
6
Loading kiln (Figure 5.3.6)
1 day
Brick makers and workers
5-8
3era Chica
No
None
7
Firing (Figure 5.3.7)
16-18 hours
Brick makers
1-2
3era Chica
Yes
PM, SO2, NO2,VOX, etc.
Depending on fuel
8
Cooling
4-5 days
Brick makers
0
3era Chica
No
None
9
Unloading kiln
1 day
Brick makers and workers
5-8
3era Chica
No
None
10
Classifying fired bricks (Figure 5.3.8)
1 day
Brick makers and workers
1
3era Chica
No
Solid waste
11
Transporting bricks to traditional selling
points and selling
1-3 days
Intermediaries
1-2
Selling points
Yes
CO2
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Extraction of clay and sands:
Clay rich soil is extracted from private and public lots located either in or near Tercera Chica. In
former times soil was extracted mainly from one private lot in the north of Tercera Chica. This Lot has
the size of eight football fields. Due to extraction the whole (!) lot is lowered approximately 1 meter
deep.
During the collection of the soil, the top layer is removed as it contains many organic impurities like
leafs and branches of bushes. The soil collected should be free from gravel, coarse sand, lime,
particle, vegetable matter, and other impurities. Extraction is done either manually or with light
machinery depending on the resources of each distributor. Distributors are usually from Tercera
Chica and acquaintances of the brick producers. Some few brick producers extract the necessary soil
themselves.
Transporting clay and sands to Tercera Chica:
The same distributor extracting the soil transports it to the kiln site where he sells it to the brick
producer. Usually the brick producer tells the distributor when the next load (either 3m 3 or 7m3) is
needed, in other words it is unusually that a distributor has a stack of soil waiting to be sold.
Mixing:
A few times the sand is passed through a sieve to remove impurities or to obtain a finer grain scale.
After finishing the work of sieving sands and clay in order to free them from organic compounds like
leafs, roots, remains of shrubs and stones the mixing begins.
Figure 5.3.2: Process step of mixing the soil, water, and additives
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The needed water is obtained from self made wells. Using a shovel and/or hands and feet a premix of
clay and wet sand is prepared until all larger lumps of clay disappear(annex: mechanic mixing). Some
brick makers add other aggregates like sawdust, rice husks, coffee husks, and ashes to the mass. This
mass is allowed to stand overnight until the smaller clumps of clay dissolve; the mixture becomes
consistent and receives the required texture for molding. The formulation and final characteristics of
the mixture are based on the experience of each craftsman and availability of materials. The mixing
usually takes place under some kind of canopy or roofing (four posts and a roof; approximately 2 by 2
meters) to protect the mixture from direct sun light. If the mass dries out clay and sand clumps can’t
dissolve completely therefore the mixture wouldn’t be homogeneous.
Molding:
Self made metal or wood molds are used to give the mass its final form. With one go three or four
bricks can be molded depending on the size and weight of the produced brick. The molds are not
standard sized; they can differ from one craftsman to another and from one region to another.
Typically very fine sand or ashes are used as a release agent to facilitate the removal of the mixture
from molds. After preparing the mold with a hand full of fine sand a clump of mass is lifted over the
head and “thrown” into the mold. In addition the mass is pushed by hand into the corners of the
mold which assures that the mass fills out the mold properly. Than the out sticking mass is cut off
with a wire. Now the filled mold is brought to the drying area and is flipped over so that the molded
mass in form of crude bricks comes out of the mold.
Figure 5.3.3: Process step molding the bricks
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Drying:
The drying usually takes place as close as possible to the molding area. Raw newly molded bricks are
placed on a drying field which is a flattened area of sandy land free of leafs. The bricks are dried
exploiting the natural action of sun and wind. In order to protect the drying bricks from rainfalls the
brick producers cover the bricks with plastic sheets. Due to the number of drying bricks the area
which needs to be covered can get quite big therefore damages can’t always be prevented (Appendix
6). None of the approximately 60 visited production sites have permanent roofing.
Figure 5.3.4: Process step of drying the molded bricks
Drying is done until according to the brick producer’s experience enough humidity has evaporated.
Sufficiently dried raw bricks are of lighter color than recently molded raw bricks. The drying period
depends on the weather and may range from five to seven days. After the third or fourth day the
brick producer turn the bricks around so that all faces are exposed to the sun and wind for even
drying, scraping off at every turn the parts that were in contact with the soil to loosen dirt and dust.
The final stage of drying includes the stacking of the bricks forming small brick walls about 1 m to
1.20 m high. This saves space and gives room for the following bricks to be dried. Now the bricks are
ready to be loaded into the kiln.
Loading the kiln:
In order to describe the loading procedure a brief description of the kiln structure is necessary
(Figure 5.3.5). The typical kiln used in Tercera Chica consists of four walls made out of adobe blocks
and has no roof. A firing chamber is located underneath ground level (1-1.5m) with one access whole
which is used to add fuels. The height of the firing chamber is approximately 1-1.5 meters. The firing
chamber is separated from the rest of the kiln by several arches made out of fired bricks. These
arches carry the weight of the unfired bricks piled on top of them. The distance from one arch to
79
another is approximately one length of a brick (approximately 24 cm). The arches are usually
oriented in a 90 degree angle to the firing access. The part of the kiln where the unfired bricks are
stacked has one sometimes two entrances (for faster loading and unloading).
Figure 5.3.5: Scotch kiln (traditional kiln) in Tercera Chica
Figure 5.3.6: Process step of loading the kiln with molded bricks
Each brick consist of two long and wide faces, two long and thin faces and two small and thin faces.
The first step of loading the kiln consists of positioning unfired bricks in a way that one half of a brick
sits on an arch and the other half bridges half of the space between the two arches. This is done
simultaneously with two bricks sitting on one of their long and thin faces. The small and thin faces
are touching each other in the middle of the gap between two arches. Immediately after positioning
these two bricks other bricks are piled on top of them in order to give the pile stability. The first two
to three layers of bricks are positioned in a 90 degree angle to the arches. Every second layer of the
following layers changes its orientation in a 90 degree angle. Bricks of the same layer keep a distance
80
of approximately 0.5 cm between each other allowing the heat generated beneath to rise thru the
whole pile and cock the bricks. Once the entire kiln is filled with unfired bricks the entrances are
closed with fired bricks. Often the bricks are piled up higher than the kiln structure itself. A kiln with a
capacity of 10,000 bricks is loaded by five workers in approximately 10 hours.
Firing:
Once the bricks are set into the kiln, the firing is started. This process normally has four stages. Each
stage corresponds to a different range of temperatures in the kiln.
 Evaporation: This stage is considered to be completed at around 120 degrees Celsius and
can be identified by white steam evaporating. Once the water contend has evaporated
the top of the kiln is closed with a mixture of dung and wet sand which is shoveled on top
of the kiln.
 Decomposition: Clay contains a vegetable matter, which breaks down at approximately
200 degrees Celsius.
 Burning: This stage requires at least the dull red heat of 700 degrees Celsius. Carbon and
sulfur present in clay are burned by the oxidation process. Most of the carbon is burnt out
at 900degrees Celsius, but some sulfur lingers until 1,100 – 1,150 degrees Celsius.
 Vitrification: This stage begins at 800 degrees Celsius and progresses throughout the firing
process rendering the bricks hard and stone-like.
Figure 5.3.7: Process step of firing the kiln
81
Firing is the most energy intensive production step of brick making. But, it differs depending on the
types of soil and kiln used. Firing a traditional brick kiln like the ones used in Tercera Chica is a
craftsmanship. According to their experiences each brick producer has elaborated a very own way of
firing depending on size and airflow which differ from kiln to kiln, raw materials and fuels. No
technological instruments like thermometers or airflow meters are used. Generally they all have one
thing in common; the temperature of the fire has to rise slowly because if the water evaporates too
fast cracks can occur and destroy the bricks. In order to do so a fire is ignited using fuels of relatively
low calorific values like saw dust, paper, and wood. Once the fire has reached a certain temperature
fuels with higher calorific values like old tiers, used oil and plastics are added. In order to reach
necessary temperatures around 1000 degrees Celsius bigger quantities of fuels are added. Depending
on the economical resources of each brick producer they either do the adding of fuels themselves or
hire workers and supervise them. The adding of fuels is done depending on the type of fuel either
with shovels (saw dust), using their bare hands (tires) or small mechanical pumps (used oil). The firing
process with traditional kilns in Tercera Chica usually lasts 16-20 hours depending on the weather,
fuel and kiln characteristics like size and airflow.
Observed fuels used in the firing production step in Tercera Chica are refrigerator insulation, used
shoes, old tires, residential waste, wood, sawdust, paper, used oil, and cables with plastic insulation.
Cooling:
The cooling period is the amount of time needed to cool off the kiln structure and the burnt bricks so
they can be unloaded by hand. The length of this period depends on following factors: the weather,
amount of fired bricks, and size of kiln and its structure (thick walls capture heat for a longer time).
Unloading the kiln and classifying burnt bricks:
Unloading and classifying burnt bricks take place at the same time. Five to eight workers (depending
on the kiln size) are needed to unload the kiln. Unloading is less time consuming than loading
because the bricks do not have to be placed carefully. Therefore one worker less is needed for
unloading.
There are basically three types of brick qualities in traditional brick production of Tercera Chica:
 Good quality bricks have a strong reddish color, a metallic sound on percussion, uniform
cubic shapes with hard edges and surfaces and no cracks.
 Poor quality bricks have a weaker red color, are not as hard as good quality bricks, and
often have little cracks.
 Over fired bricks have broken apart or have melted and lost their cubic shape; under
fired bricks are still raw and pulverize easily.
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Figure 5.3.8: Process step of classifying burnt bricks
While unloading the kiln the workers qualify and pile the bricks close to the kiln according to above
mentioned characteristics. Sometimes due to the strong competition on the brick market the bricks
are unloaded even though they haven’t cooled off totally. In times of high demand the bricks are
directly loaded onto a truck and transported to the selling points thru out the city. In times of low
demand the burnt bricks are stored on site. The prize for 1.000 good quality bricks is approximately
650 MXN.
Transporting bricks to traditional selling points and selling:
Big construction companies tent to buy high quality construction materials from firms with
mechanized production processes at higher prizes and focus on bigger projects like public buildings
and big scale residential constructions.
5.3.3. Observation of child labor
Four cases of child labor were observed throughout the investigation. Minors of 8, 12 and 14 years of
age have been working in following production steps: mixing, molding and drying (flipping the crude
bricks so they can dry evenly).
5.3.4. Conclusion
The traditional brick production process is a very labor and time intensive process. Barriers to enter
the traditional brick production are very low because the construction of a traditional kiln is easy and
cheap. Due to the current market situation (according to brick producers there is a low demand and
high competition) margins are very low. Low margins do not allow costly production modifications
such as mechanization not to speak of more efficient kiln designs which are generally more cost
intensive construction vise (a Vertical Shaft Brick Kiln with a capacity of 66.000 bricks per month
accounts of construction costs of approximately 15.000 USD according to PRAL, 2009).
83
Therefore low cost approaches to reduce energy losses and fuel consumption are basically the only
way to increase the margin. But most of these approaches (geometry, orientation of firing access,
size, etc.) can only be taken in consideration before and during the construction phase of a
traditional kiln (during the investigation only one kiln was being constructed). Few low cost
approaches like closing cracks and gaps in order to lower energy losses, sufficient drying of crude
bricks, and sufficient drying of fuels e.g. sawdust and other biomasses in order to lower energy losses
can be applied after the construction phase and therefore can lower production costs and increase
margins to some degree. But most of the documented kilns are in such a bad condition that
renovation and maintenance would use up nearly all of the increased margins. It seems as if the brick
producers are stuck in a vicious circle.
The brick producers from Tercera Chica are aware of the contamination they are causing due to the
fuels they are using. Therefore they have tried to find reliable sources of less contaminating fuels like
gas, sawdust and recycled oil. These fuels are either scarce or very costly compared to residues like
old tires and residential waste which hinders their use.
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5.4. Participative workshops in Tercera Chica with the traditional brick makers
Two participative workshops were realized, which took place in the gathering hall of the brick
producer’s cooperative in the district Tercera Chica. The convocations were established by the
president of the brick maker’s cooperative.
5.4.1. Methodology
The first workshop was on 7th of November 2010, where 38 of 76 members of the brick producer’s
cooperative were present. The first workshop aimed to present an introduction of cleaner
production methods and strategy options such as relocation and cooperatives, within the scope of
traditional brick making. As an alternative kiln type the Vertical Shaft Brick Kiln (VSBK) was
introduced. Questions of brick producers were answered and information about already known or
applied methods was collected. The duration of the workshop was 2 ½ hours using a power point
presentation and two videos explaining the functionality of a VSBK (a documentary of traditional
brick producers in Peru and their experiences with the VSBK, and an animation explaining the
functionality of the VSBK).
5.4.2. Results of the first workshop
5.4.2.1.
Good housekeeping
The participants explained that they already tried to integrate some of the shown good
housekeeping practices (Table 5.4.1). According to them, they mixed sawdust into the bricks, but the
result was poor, it neither shortens the fuel usage nor the firing time. Some of the participants
indicated that the soil used in Tercera Chica is too “hard” which is supposed to be the reason why the
process of firing takes longer compared to others informal brick producing areas.
Table 5.4.1: The experience of good housekeeping methods of the traditional brick makers in Tercera Chica
Good housekeeping method
Brick maker experience
Result
Big kilns
Not common
Squared kilns
Common
Better
insulation
measures aware but not implemented
(thicker walls)
Fuel close to bricks
Not implemented
Coal which can be distributed
close to the bricks is not available.
Bricks should be properly dried Implemented: still sometimes the Lack of knowledge about the right
before firing
product comes out over fired or point of dryness of the bricks.
under fired.
Unevenly distributed temperature
in kiln (incorrect air flow).
Fuels should be dry
Implemented
Kiln control (Air flow control)
Not common
Bricks are under fired or over fired.
Alternative fuels like agricultural Implemented: sawdust was mixed The fuel usage and firing process
residues should be mixed into the into the raw material of the bricks. was not shorted. Sawdust is not
raw bricks
mixed into the brick material
anymore.
85
Good housekeeping method
Kiln located in a 90o angle to the
wind direction
Continues kilns
Brick maker experience
Not common
Result
Not implemented
Most of the good housekeeping methods are not common among the brick producers in Tercera
Chica, which could indicate a lack of instruction among brick producers. It is obvious that the brick
producers are not familiar with good housekeeping methods e.g. maintenance of the kiln. One
reason for that could be, that in San Luis capacity building programs for brick producers do not exist.
Most programs which are established by other Mexican states are supporting the change of clamp
kiln to a new and more efficient kiln design. Being aware of these programs some brick producers
neglect e.g. the maintenance of their kilns hoping that a similar program will be implemented in San
Luis as well.
Also should be mentioned that many good housekeeping methods concerning the kiln design such as
squared kilns, big kilns, and orienting the kiln’s firing access in a 90° angle to the dominant wind
direction cannot be applied to existing kilns but only to kilns yet to be constructed.
5.4.2.2.
Product modification
According to the brick producers there have already been some intentions to change the product’s
size, color, and the material composition in order to diversify the product on the market. The client
market in San Luis is not interested in new brick designs and was not prepared to buy better quality
and bigger brick sizes at a higher price.
According to experiences of traditional brick producers from Ciudad Juarez and San Luis higher
quality and higher prices of bricks are commonly rejected by the market (personal communication,
2009). Nevertheless there are some product modifications, such as changing the size and including
air gaps can lead to using fewer raw materials for the bricks, which could lower the existing
production costs. This kind of product modification should include a public campaign explaining its
advantages, given that the client market in San Luis still prefers the established size of bricks.
Concluding can be said that there are basically two options for brick producers to increase their
margins: one is lowering the production costs and the other is producing a brick of higher quality in
order to sell it at a higher price. As mentioned above the clients are not willing to pay more.
Therefore lowering the production costs seems to be the only option within the brick producers’
scope of action. Another option would be governmental incentives e.g. green bricks, but this is
beyond the influence of the traditional brick producers.
86
5.4.2.3.
Input substitutions (fuels)
Propane and natural gas is too expensive in San Luis.
5.4.2.4.

Mechanization and new brick kiln design
Mechanization
The metering pump for solid fuels such as biomass (dosificadora sold by PMT Grupo Industrial) was
presented among other semi-mechanization techniques. The metering pump was presented in detail
by showing its main characteristics. A commercial video made by PMT Grupo Industrial explaining the
product in a more detailed manner was shown.
According to the brick producers some few of them have worked with a metering pump using
sawdust as fuel generating good results in terms of brick quality and fuel consumption however it is
very time intensive to collect enough bio-fuel (mainly sawdust from carpentries). Nevertheless the
brick producers’ association is trying to reach out for financial support from the local government to
buy a metering pump for solid fuels.
Conclusion: The traditional brick producers of Tercera Chica are willing to mechanize their production
process. Their economic condition complicates to buy and operate most of these machines. Even if
the cooperative collects money to buy a metering pump (price see Appendix 7) it would just be one
machine for too many brick producers.

New brick kiln design
Different Kiln designs were presented; however the focus was the Vertical Shaft Brick Kiln. The main
characteristics of the VSBK were explained using photos and abstract drawings. Also two short
documentary videos were shown. The first one is an animation done by Saijd Atthar (2009)
explaining the functionality of the VSBK in a detailed manner. The second movie gives an insight into
an already accomplished VSBK project in Peru. It is made by Swiss Contact and its project partners
(PRAL) and talks about the experiences made by the involved brick producers.
This part of the workshop caught the brick producers’ attention the most. They wanted to know
more about the technical properties of the VSBK, the price and who could support them in SLP to
build the VSBK. When mentioned that Swiss Contact and GTZ have accomplished projects in South
America and Asia introducing the VSBK the desire was expressed to get in contact with above
mentioned organizations in order to obtain more detailed information and to find out whether or not
a project like the one shown from Peru would be feasible for Tercera Chica. The participants also
expressed the request if the presentation concerning the VSBK could be repeated on a reunion
between brick producers of Tercera Chica and state government officials/authorities.
87
Conclusion: As already mentioned before the brick producers are mostly interested in new kiln
designs to become more energy efficient (which lowers production costs and lessens the
environmental impact). The obstacle is that there are no governmental programs to change the kiln
design in SLP and the association of brick producers in Tercera Chica has not the financial funds and
knowledge to build new kiln designs. Also negative experiences with governmental programs such as
the implementation of the MK2 make new approaches more difficult.
The VSBK is usually operated with coal, but new experiences of NGO’s in Ecuador and Nicaragua
show that the VSBK can be operated as well with bio-fuels (Moreno, personal communication,
2010)25. This requires further investigation of possible synergies with the local agricultural sector and
fabrics which produce bio wastes.
5.4.2.5.
Relocation
A relocation project concerning Grupo Ladrilleros y Artesanos la Tercera Chica A.C. was intended to
be applied by the former municipal government of SLP. A terrain approximately 20 km north of
Tercera Chica in a rural area was chosen and a MK2 with the help of the Universidad Autonoma
Chihuahua was built so that the brick producers could run a series of firings. The program was
neglected by the brick producers because (according to brick producers):
 Brick producers weren’t involved in choosing the terrain.
 The ownership of the terrain was unclear (whether the terrain would be granted to the
brick producers, rented, or sold).
 The terrain was too small for all brick producers of the cooperative.
 The terrain didn’t feature water supply nor electricity (later on a generator was
supposed to be installed).
 The constructed MK2 didn’t deliver well burned bricks, was difficult to load and unload
(due to its shape; round with a dome), and for most brick producers had insufficient
capacity with only 9500 bricks.
 The brick producers weren’t involved in the construction of the kiln but were supposed
to build the following kilns on their own.
 The terrain being located rather far away from their homes appeared to be unsafe. Brick
producers had concerns that tools and burned bricks could be stolen in their absence.
25
Moreno works for Ecosur which is a network of different NGOs working with brick producers in different
countries in Latin America.
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The construction of shacks for spending the night while firing which can last up to 20
hours was not allowed.
 With the change of the government in 2010 the project was dropped.
Taking a look at the carefully elaborated relocation project of the Universidad Autonoma Chihuahua
in Ciudad Juarez makes it hard to believe that its participation in this project involved more than the
construction of the MK2. The stated reasons for the refusal rather indicate a lack of communication
between the municipal government of San Luis and the brick producers of Tercera Chica. It also
seems as if the project wasn’t well organized. According to the brick producers the owner of the
terrain appeared during one test run of the kiln asking what they were doing on his property and
who gave them permission to build the kiln. Despite the fact that the legal status of the terrain was
unclear it also wasn’t chosen well. Water and in parts electricity are essentials for the brick
production process. Also with not involving the brick producers in the decision making process they
felt left out and ignored which led to frustration.
5.4.2.6.
Cooperatives
The brick producers of Tercera Chica formed a legal cooperative in 2004. Its name is Grupo
Ladrilleros y Artesanos la Tercera Chica A.C. (A.C. stands for associación civil). It currently has 76
members and is led by an executive board of 5 brick producers of which one is the
president/spokesman. The executive board is supposed to be elected every two years. Nevertheless
the board hasn’t changed because its 5 members are highly respected and trusted. Also the other
members are not willing to spend extra time which naturally comes with such a position. The
cooperative gathers every first Sunday of each month in a small hall which is allocated by the
president. Each member of the cooperative including the executive board pays 20 MXN. per month
as a member fee. The generated money is used to help injured or sick members financially, to pay for
office supplies which are needed addressing problems to the government, and to pay for travelling
costs to other brick producers in neighboring states in order to find applicable alternatives for the
production processes in Tercera Chica (journeys to following cities were undertaken los Cuarenta,
Zacatecas, Guanajuato and Aguascalientes).
During their meetings internal and external problems are addressed. The cooperative tries to
negotiate with the municipal government about possibilities to develop strategies and programs to
improve the economical and environmental conditions.
The group has good connections to Universidad Autonoma San Luis Potosi which led to several
projects that are being conducted including this thesis.
89
The brick producers of Tercera Chica are well organized. This cooperative seems to strengthen their
will to keep searching for alternatives for their current production process. Nevertheless some brick
producers have left the cooperative due to the frustrating fact that the communication between
them and the municipal government hasn’t led to fruit baring results. In fact they have little trust in
the municipal government. They are well aware that the organized structure of their cooperative can
help implementing projects designed by institutions such as the Universidad Autonoma San Luis
Potosi. Due to their good experiences with a number of students from the Universidad Autonoma
San Luis working on their master theses, doctorates, and post doctorates in studies concerning
Tercera Chica they have high hopes that with the help of the university a project addressing the
number of problems that are existent in their surrounding may be implemented.
5.4.3. Second participatory workshop: SWOT analysis
5.4.3.1.
Methodology
The second workshop took place on 5th of December 2010 and was a sequel of the first workshop.
Together with the brick makers in form of an open discussion a SWOT-analysis for each of the
different methods introduced in the first work shop was carried out. 40 brick producers were
present. Three of them were not present at the first workshop. In the first part of the workshop
following unanswered questions from the first workshop were answered.
 How many persons are needed to operate a Vertical Shaft Brick Kiln?
 How much does a Vertical Shaft Brick Kiln cost?
 How many brick can be produced with the Vertical Shaft Brick Kiln?
 How much area is needed to operate the Vertical Shaft Brick Kiln?
 Can any type of soil be used for the production of bricks with the Vertical Shaft Brick
Kiln?
 Can used oil be applied as fuel for the Vertical Shaft Brick Kiln?
 How is the Vertical Shaft Brick Kiln lit?
5.4.3.2.
Results of the second workshop
In the second part of the workshop the brick producer’s opinions on the following issues which were
presented in the first workshop are documented using the SWOT analysis (Spanish: F.O.D.A). First the
SWOT analysis and its benefits were explained to the brick producers and then each point was
analyzed together.
90
Threats:
 Costs (fuel)
 Constant assured fuel supply is needed
 Low demand but production has to continue
uncontrollable
Opportunities:
Changes in brick types demanded by the market
controllable
Table 5.4.2: SWOT: Vertical Shaft Brick Kiln
Strengths:
Weaknesses:
 Steady income
 Costs (kiln construction)
 Different type of bricks can be fired almost  Change of working hours (8 or 12hour shifts
instantly
24/7)
 Lack of knowledge operating the kiln
Actions assumed to turn weaknesses and threats into strengths and opportunities:
 Costs (kiln Construction): financial aid could be generated by implementing a project with
authorities like the local university and or aid agencies like GTZ and Swiss Contact. Many
brick producers have experiences in construction work like masonry. Therefore parts of the
construction could be accomplished by themselves.
 Change of working hours: organizing the involved workers in form of working schedules
could help planning their spare time (family, additional job etc.).
 Lack of knowledge operating the kiln: due to the fact that there is no VBSK operating in
Mexico yet, somebody able to train them on the job is needed (developing agency, NGO,
experienced with VSBK).
 Costs for fuel/constant supply: As the VSBK functions with either pulverized coal (not
available in SLP) or biomass cut in fine pieces a constant source assuring a stable prize
should be found.
 Low demand but production has to continue: The VSBK is a continuous kiln which is one
important part of its high efficiency. Therefore a certain amount of clients with high
demands needs to be generated (e.g. Construction firms).
Table 5.4.3: SWOT: Good practices
Weaknesses:
 Extra effort (time consuming)
Threats:
91
uncontrollable
Opportunities:
 Could be recognized by the municipal
government as an effort to lower contamination
controllable
Strengths:
 Lower fuel consumption
 Lower contamination
 Easy to apply and low cost
 Higher margin
Actions assumed to turn weaknesses and threats into strengths and opportunities: The group could
only think of positive effects of good practices willing to spend extra time to apply them if possible.
Threats:
 Costly
 Insecure fuel supply (biomass)
 Fuel needs to be dry and cut
uncontrollable
Opportunities:
Table 5.4.4. SWOT: Mechanization (Dosificadora)
Weaknesses:
 Don’t know how to operate the machine
 Electricity needed
controllable
Strengths:
 Lower fuel consumption
 Higher margin
 Less contamination
Actions assumed to turn weaknesses and threats into strengths and opportunities:

Operating the machine: The company selling the machine has to assure an introduction on
how to operate it, which could result in classes given by them to other brick producers.

Electricity needed: Costs for generators and connection to the grid must be researched and
evaluated.

Costs of the machine: Cost for a few machines could be split between brick producers.
Sharing a few machines could lead to lower maintenance and reparation costs. Some sort of
organization would be necessary (who occupies the machine when and for how long).

Insecure fuel supply of biomass: Constant source assuring a stable prize needs to be found. If
several brick producers share a machine this group could organize fuel supply together.
Threats:
 Has to be dry and cut
 Transport is costly (scarcity in the region)
 Insecure fuel supply due to crop failure
uncontrollable
Opportunities:
controllable
Table 5.4.5: SWOT: Biomass as fuel
Strengths:
Weaknesses:
 Less polluting as present fuels (plastics and old  Has to be dry and cut
tires)
Actions assumed to turn weaknesses and threats into strengths and opportunities:

Has to be dry and cut: preferably should be bought dry and cut, because drying and cutting
are time and labor intensive. Could be done by the brick producers themselves but would
generate additional costs. A research of agricultural producers generating residues which are
naturally dry and small (e.g. coffee husks) should be undertaken.
92

Transportation: the only action the group could think of was buying biomass as a group at
lower prices, so that costly transportation cost could level out.

Insecure fuel supply due to crop failure: a number of different types of biomass which are
applicable (dry and small or already cut) could be bought. Biomass could also be bought from
different regions (e.g. Huasteca, Guanajuato).
Threats:
 Easier to control by government
uncontrollable
Opportunities:
 Foundation for implementation of projects with
authorities
controllable
Table 5.4.6. SWOT: Cooperative
Strengths:
Weaknesses:
 Think pool
 Difficulties communicating with institutions
 Exchange of experiences
 Due to lack of time few want to take
 ‘We are stronger together’
responsibility of representative positions
 Member fees giving the possibility to act and  Some have left because positive results were
support
lacking
Actions assumed to turn weaknesses and threats into strengths and opportunities:
 Difficulties communicating with institutions: help of a lawyer, NGOs, development agencies
and/or institutions of confidence such as the local university could be consulted.
 Lack of members willing to take representative positions: positive process needs to be
achieved so that more members understand the importance of the cooperative and become
willing to take responsibilities.
 Leaving of members: positive process needs to be achieved so that more members
understand the importance of the cooperative and become willing to take responsibilities.
 Easier to control by government: it was mentioned by on brick producer that information
gathered by e.g. students of the UASLP could be used from municipal institutions to sanction
or install laws which could make their production process more costly. But the majority sees
projects like this thesis as a chance for positive progress.
93
Threats:
 Security (if estate is located outside the urban
area stealing of bricks and tools could occur)
 Insufficient infrastructure (water, electricity)
uncontrollable
Opportunities:
 Could lead out of informality
controllable
Table 5.4.7: SWOT: Relocation
Strengths:
Weaknesses:
 All producers working in one place (buying and  Bigger distance to their homes which creates
selling together could lead to better margins)
transportation costs and difficulties supervising
children
 Insufficient infrastructure (water, electricity)
Actions assumed to turn weaknesses and threats into strengths and opportunities:
 Distance to homes: if a relocation project would be implemented the participation of brick
producers would be essential for their cooperation in such a project. This way they could
assure that good public transport is existent. No possible actions to assure child supervision
were found.
 Insufficient infrastructure: their participation would assure that a chosen terrain had
necessary infrastructure. In parts wells could be dug and generators could be applied.
 Security: some sort of organizing themselves so that at least a few brick producers are always
present.
Strengths:
uncontrollable
Threats:
 Low demand
 Low demand of alternative brick types
 High competition from other brick producing
communities like Villa de Reyes
controllable
Opportunities:
Table 5.4.8: SWOT: Market situation
Weaknesses:
 Bricks are sold by distributors because trucks are
not available and waiting for costumers is time
consuming
 Low margin
 (Bricks are of low quality)
Actions assumed to turn weaknesses and threats into strengths and opportunities:
In general the market situation was very negatively described and almost no actions were found.
 Bricks are sold by distributors: an action mentioned was a relocation project where all brick
producers work in an organized form in one place interacting with their clients as a group.
94
 Bricks are of low quality: this weakness was suggested by the interviewer. No action was
found by the group.
 Low margin: no action was found by the group.
 Low demand: no action was found by the group.
 Low demand of alternative brick types: no action was found by the group.
 High competition: no action was found by the group.
5.4.3.3.
Conclusion
The second workshop showed that the members of Grupo Ladrilleros y Artesanos la Tercera Chica
A.C. are open to new approaches. They are aware of the fact that their production process is
contaminating the environment and has its effects on their own health and the health of residents.
Also the difficult market situation, with low demands and high competition, forces them to search for
alternatives which could lead to higher margins.
The introduction of the VSBK was of great interest to them. Many detailed questions were asked
showing expertise in technical and organizational matters. Due to the lack of inexpensive fuels which
can compete with highly contaminating waste materials like tires, plastics etc. the implementation of
the VSBK is seen as difficult.
Mechanization in general is of their interest but difficult to apply due to the high costs of machines,
additional fuels needed to operate them, and maintenance costs.
Alternative fuels such as biomass appear to be of interest to them as well, but are seen as to cost
intensive due to their transportation from areas such as Huasteca (250 km away). In matter of fact
the struggle to find fuels is dominating their preoccupation. Alternative fuels have to be at least as
inexpensive as current used waste materials in order to be considered as an alternative.
The brick producers’ perception of the municipal government is very negative due to made
experiences (intended relocation project which failed) and communication difficulties between the
two stakeholders. Universidad Autonoma San Luis Potosi is generally trusted due to a number of
researches currently being undertaken. Hopes are high among brick producers that with help of the
Universidad Autonoma San Luis Potosi a project addressing their problems might be implemented in
the future maybe involving a developing agency.
Nevertheless the workshops also show that there are some measures which can be undertaken by
the brick producers themselves in order to lower contamination and fuel consumption (good
practices). According to their perception these measures are of rather little impact, but a step into
the right direction.
95
The brick producers highly value their cooperative even though it hasn’t bared overwhelming
positive process yet. They are convinced that working in a group is the only way out of their difficult
situation.
96
6. Conclusions and recommendations
The kiln type used in Tercera Chica is one of the most energy inefficient designs found during this
investigation. The average age of the located kilns is 19.7 years and more than half of them are in
poor or very poor conditions. The current condition of the majority of the kilns indicates that
maintenance is not regularly carried out. Through cracks in the kiln structure heat is lost which
causes higher fuel consumptions. If brick producers were aware of the amount of money being lost
due to cracks and leaks measurements could be easier taken to prevent these losses. This could lead
to less production costs and therefore increase brick producers’ margins. Also emissions would
decrease and thus the health and environmental impacts. A capacity building program explaining
why and how maintenance of kiln structure is important could have a positive impact since most
brick producers are already asking for this form of assistance.
Synergies between brick producers and any kind of source producing preferably dry biomass as a
waste product could result in a win-win situation. Brick producers could buy an alternative fuel at a
low price and the producers of these fuels, which to them are waste products, could generate an
additional income. Barriers applying an alternative fuel are relatively low because most brick
producers already have experiences with other fuels and, even more important, are trying to find
alternative fuels themselves in order to decrease their emissions (e.g. some brick producers are
collecting sawdust from carpentries located in San Luis). Obviously alternative fuels have to be
cheaper than or at least as cheap as current fuels (tires, garbage, etc.) in order to be applicable. A city
wide garbage separation program could be a sufficient source generating enough biomass to supply
brick producers. But such a program needed to be initiated and carried out by the local government.
The kiln comparison of this investigation identified the Vertical Shaft Brick Kiln (VSBK) as the most
efficient kiln applied in informal brick production. Nevertheless the VSBK might be difficult to
implement in Tercera Chica due to following reasons: its rather high construction costs of
approximately 15,000 USD, its constant fuel need (continuous production), the types of fuel
applicable (pulverized coal, dry biomass), and the fact that instructions on how to operate the kiln
must be given to the brick producers in order to operate the kiln. These obstacles make it almost
impossible for the brick producers to implement the VSBK on their own. Therefore they need the
help of qualified and experienced institutions/organizations. Such organizations could be the GTZ
which has carried out several projects concerning the VSBK in Asia and Swiss Contact which has
recently implemented the VSBK in the southern part of Peru.
The socio-economic conditions of brick producers participating in the carried out surveys are poor
(dwellings, transportation, health insurance, education) but not as poor as the overall situation in
97
Tercera Chica. Nevertheless this could change in the future due to steady rising competition which
could force brick producers to lower the prices of their bricks resulting in lower margins.
The informal brick production is often a family business which is passed on from generation to
generation. In order to cut costs minor family members are involved (labor is a costly part of brick
production) at young ages. Due to the time consuming work in brick production and lack of financial
resources young family members don’t have access to a higher education permitting them to leave
the informal sector and work formally. This often results in the perception that the family business is
the only chance to find work. Therefore members of such a family business have little chance to
escape poverty.
As the literature review of this investigation shows the emissions from traditional kilns using fuels
such as tires, used oil, and residential garbage etc. can have an impact on the environment and the
human health. The brick producers are aware that their kiln emissions are contaminating but neglect
the possible impacts on their own health. Workshops addressing health risks in brick production not
only for brick producers but also for close by residents especially children could be an important part
to change their awareness.
Brick producers’ hopes lay on their cooperative. After frustrating attempts to approach governmental
institutions and a failed relocation program some brick producers have left the cooperative.
Nevertheless motivation among members of the cooperative is high, notable by their efforts to
improve their situation. The wish to pollute less while having the same income was expressed several
times during this investigation. They are interested in applying for green subsidy programs and clean
development mechanisms (CDM) but lack partners like governmental and non-governmental
institutions. Distrust towards the government is high which is why the cooperative prefers to seek
collaborations with institutions like the UASLP.
Due to high competition brick producers are willing to organize themselves in single place outside the
urban area hoping to increase their margins by buying raw materials and selling bricks as a group
directly to their clients bypassing intermediaries. A relocation project including the implementation
of a more energy efficient kiln design could result in the production of uniform bricks with of similar
quality (since raw materials, fuels, and kilns are the same). Assuring large brick quantities of the same
quality could attract bigger costumers like construction companies. In order to carry out such a
relocation project the participation of the brick producers is crucial as failed relocation attempts
show. The relocation area should fulfill following requirements: it shouldn’t be located too far from
the brick producers’ homes and should be accessible with public transportation since few members
of the cooperative own a car; it should be as close to raw materials as possible in order to lower
transportation costs which can lead to higher margins; it should feature sufficient infrastructure
98
(water, electricity); it should be big enough for all members of the cooperative; and the tenure of the
property should be clear. Also a land-use plan assuring that future settlements can’t envelope the
area and force the brick producers to move again should be considered. After the implementation of
a relocation project brick producers probably will continue to function as family businesses which
includes cases of child labor, but over time chances are that with higher margins child labor might
become unnecessary.
6.1. Recommendation for further studies

Further studies are necessary in order to find out if fuels such as dry biomass are available in
sufficient quantities and at acceptable prices. This investigation tried to locate fuels of these
characteristics but couldn’t come up with positive results due to problems of contacting
potential sources (e.g. agriculturists who are mainly situated la Huasteca which is a remote
region of the state; forestall institutions in charge of public parks (Tangamanga I and II) of
San Luis Potosi).

Energy efficiency study of informal brick kilns (see Mason, 1998).

Compressive strength tests with informal sector bricks for classification (see Mason, 1998).

Clean development mechanisms (CDM) and certified emission reduction (CER) in the informal
sector.
Adaptability studies of construction materials with low energy production processes in urban multi
storey buildings:

Adobe

Compressed earth blocks (CEB)

Stabilized compressed earth block (SCEB)

Currently under development: Synthetic sandstone/ bacillus pasteurii (Prof. Ginger Dosier at
American University of Sharjah, United Arab Emirates)
99
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Appendix 1: Kiln comparison
Introduction
A literature review was carried out in order to compare important characteristics of different kiln
types which are in use in different developing countries around the world. Due to the lack of further
literature on this subject only the two following sources were used:
 Brick by Brick,Heierli and Maithel; 2008
 Small-scale brickmaking, ILO; 1999.
Different types of brick kilns
Brick kilns can be divided into two main groups which are intermittent kilns and continuous kilns.

Intermittent kilns:
In intermittent kilns, bricks are fired in batches. Generally, bricks and fuel are stacked in layers and
the entire batch is fired at once; the fire is allowed to die down and the bricks cool off after they have
been fired. The kiln must be emptied, refilled and a new fire started for each load of bricks. In
intermittent kilns, most of the heat contained in the hot flue gases, in the fired bricks and in the kiln
structure is thus lost. Clamp, scove, scotch, and downdraught kilns are examples of intermittent kilns.
Such kilns are still widely used in several countries in Asia, Africa, and South and Central America as
well as in some parts of England and Belgium (ILO; 1999).

Continuous kilns:
In a continuous kiln, on the other hand, the fire is always burning and bricks are being warmed, fired,
and cooled simultaneously in different parts of the kiln. The heat in the flue gases is utilized for
heating and drying green bricks, and the heat in the fired bricks is used for preheating air for
combustion. Due to the incorporation of heat recovery features, continuous kilns are more energyefficient (ILO; 1999).
Continuous kilns can be further sub-divided into two categories: moving-fire kilns and moving-ware
kilns.
In a moving-fire kiln, the fire moves progressively around a closed kiln circuit while the bricks remain
stationary. The kiln circuit can be oval, rectangular, or circular. Because of the counter flow
arrangement, the incoming air encounters hot bricks exiting from the combustion zone. As such, air
is preheated (and bricks are cooled) before entering the combustion zone. The combustion products
(flue gases) from the combustion zone pass over the green bricks, resulting in the preheating of
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bricks (and cooling of flue gases). The fire travels in the direction of airflow. A chimney stack and/or a
fan provide the necessary draught (ILO; 1999).
Bull's Trench Kilns, an important kiln type for firing bricks in South Asia, are an example of a moving
fire kiln. In a moving-ware kiln, the fire remains stationary, while the bricks and air move in countercurrent paths. In a tunnel kiln, a horizontal moving-ware kiln, bricks to be fired are passed on cars
through a long horizontal tunnel. The firing zone is located at the centre part of its length. Cold air is
drawn from the car exit end of the kiln and is cooling the fired bricks. The combustion gases travel
towards the car entrance losing a part of their heat to the entering green bricks. The cars can be
moved either continuously or intermittently at fixed time intervals. The tunnel kilns have provision
for air extraction and supply, at several points along the length of the kiln (ILO; 1999).
The vertical shaft brick kiln (VSKB) is another example of a moving-ware kiln. In this kiln the
movement of bricks is in a vertical downward direction, and upward air movement is generated by
natural convection (ILO; 1999).
In general, large kilns are more economical on the use of fuel than small kilns as less heat is lost
through the proportionally smaller outside area of the kiln. Thus, separate teams of brick producers
may use the same large kiln on a co-operative basis, and thus benefit from lower firing costs(ILO;
1999).
Kiln description (intermittent kilns)

Clamp kiln
The clamp is the most basic type of kiln since no permanent kiln structure is built. It consists
essentially of a pile of green bricks combined with combustible material. Normally, the clay from
which the bricks are molded also includes fuel material (e.g. sifted rubbish, small particles of coke,
coal dust with ashes, breeze).
A flat, dry area of land is first chosen, and a checker work pattern of spaced out, already burnt bricks
laid down over an area of approximately 15 m by 12 m. Fuel in the form of coke, breeze is then
spread between the checker work bricks, covering the latter with a layer at least 20 cm thick. Dry,
green bricks are next closed-laid on edge upon this fuel bed (ILO; 1999).
A clamp is generally made up of approximately 28 layers of bricks. Its sides are sloped for stability.
Three or four holes (a.k.a. ‘eyes’ of the clamp) at the base of one of the clamp walls are formed in
order to allow the initial ignition of the fuel bed. Two courses of already fired bricks are next laid on
top of the green bricks for insulation purposes. Fired bricks are also laid against the sloping sides of
the clamp as it progresses. Sometimes, a second thin bed of fuel is laid at a higher level in the clamp
(ILO; 1999).
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Once several meters of the length of the clamp have been built up, the fuel bed may be ignited with
wood stuffed into the eyes of the clamp. The latter are bricked up with loosely placed burnt bricks
once the fuel bed is alight. As the fire advances, more green bricks are built into the clamp (ILO;
1999).
The rate of burning is not easily controlled and depends upon several factors, including wind strength
and direction. Wind protection like screens can help control the temperature. Ventilation, and hence
burning rate, can also be controlled, to some extent by an adjustment of the burnt brick covering the
top of the clamp. For example, these bricks may be spaced out or removed in order to speed up the
firing of the bricks in a given area. Conversely, they may be tightened up or covered with ashes in
order to slow down the burning rate. It is desirable to have the fire advancing with a straight front at
a steady rate. Bricks close to the edges of the clamp will tend to be under fired as a result of higher
heat losses. This may be partially rectified by placing a little more fuel near the edges of the clamp.
Extra fuel may also be spread between the top bricks during firing (ILO; 1999).
The firing process is indicated by the sinking of the top of the clamp. Under the right circumstances,
the latter will settle evenly. Once the fire has passed through a particular point, the bricks start to
cool. If enough air flows through the bricks during firing, the oxidizing process will give them a red
color. Where air is scarce, reducing conditions due to the gases from the burnt fuel will yield orange
or yellow bricks, especially if limy clay is used for molding. Variations in colors are normal even on a
single brick face (ILO; 1999).
As the fuel is in close contact with the green bricks, the fuel efficiency of a large clamp of 100,000 to
1 million bricks can be fairly high (e.g. about 7,000 MJ per 1,000 bricks). Smaller clamps will be less
efficient, as a result of the greater proportion of outer cooling area for a given volume. However,
they may be operated successfully with only 10,000 bricks (ILO; 1999).
The bricks near the centre of the clamp will be the hardest. Others should be sufficiently good for
many uses. However, 20 per cent of the bricks may still not be saleable. Fortunately, many of these
rejects can be put into the next clamp for re-firing, or used in the clamp base, sides or top (ILO;
1999).

Scove kiln
A widely used adaptation of the clamp is the scove kiln, also mistakenly called a clamp. If the fuel
available is of a type which cannot be spread as a thin bed at the base of the kiln and/or is not in
sufficient quantity to burn all the bricks without the need for replenishment, tunnels can be built
through the base of the pile in order to feed additional fuel (figure VII.3). This is a suitable method of
burning wood, the latter being one of the most frequently used fuels for small-scale brick making in
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developing countries. Usually, the outer surface of the piled-up bricks is scoved, that is to say
plastered all over its sides, with mud (ILO; 1999).
The construction of a scove kiln requires a level and dry area of land. Previously fired bricks, if
available, lay bed face down to form a good, flat surface. Three or four layers of bricks are used to
form the bottom of the tunnels. The width of each tunnel is approximately equal to that of two brick
lengths. Three lengths of bricks separate the tunnels. Alternate courses are laid at right angles to
each other (a course of headers, followed by a course of stretchers). Two short tunnels
(approximately 2 m long) may be sufficient for a small number of bricks. For large numbers of bricks,
tunnels cannot be longer than approximately 6 m. Otherwise, fuel inserted from both ends will not
reach the centre of the tunnel. Large numbers of bricks are dealt with by extending the number of
tunnels to cope with the requirement (ILO; 1999).
The fourth and successive courses of bricks are laid in such a way that rows of brickwork finally meet,
and tunnels are thus completed. Green bricks are set above tunnel level, in alternate courses of
headers and stretchers up to a height of at least 3 m above the ground. At the edge of the scove,
each course is stepped in a centimetre or so, to give a sloping side. Small spaces are left between the
bricks to allow the hot gases from the fires to rise. The required maximum spacing between bricks is
a ‘finger width’. This is easy to achieve although a narrower spacing may be satisfactory. As the scove
is built up, an outer layer of previously burnt bricks is laid, to provide insulation. This will also allow
the proper firing of the outer layers of green bricks (ILO; 1999).
On the top of the green bricks, two or three courses of previously fired bricks are laid, bed face down
and closely packed. The whole structure should then be scoved with wet mud to seal air gaps. Turf is
sometimes laid on top to reduce heat losses. The wet mud should not contain a high fraction of clay
if cracks are to be avoided during firing. Some of the top bricks half-way between the tunnels must
not be scoved so that they may be lifted out to increase air flow through the kiln as required. The
provision of this adjustable ventilation can be most useful in controlling the rate of burning (ILO;
1999).
Firewood is set into the tunnels for firing. It should preferably be at least 10 cm across, in pieces
about 1 m in length. Kindling should be set in the mouth and bottom of the tunnel. Since the heat of
the fire is to rise up into the bricks, it is essential that strong winds do not blow through the tunnels,
cooling bricks down, and wasting heat. Such winds may increase fuel consumption by 25 per cent. A
number of measures may be taken to avoid this waste of heat, including the blocking of the centre of
the tunnel during construction, or the temporary blocking of tunnel mouths with bricks. In the latter
case, one end may be bricked up and fire set at the other end. Once the fire is well alight, that end
may be bricked up while the previous one is opened and lighted. Thereafter, the fires may be
111
controlled by bricking up tunnel mouths with loose bricks and adjusting the vents on top. As fuel
burns away, it must be reloaded (ILO; 1999).
As with all kilns, heat must be gentle at first until all the water in the bricks is driven off. Adequate air
flow is therefore essential to remove the steam produced. Thus, the vents should be open, and the
fires kept low so long as steam is seen to rise from the top of the scove. This water smoking period
may last several days (ILO; 1999).
Once the water smoking stage is completed, the fires may be built up gradually to increase
temperatures up to a maximum over a period of a few days. A maximum temperature is indicated by
the charring of dry grass or paper thrown on top of the scove, or the appearance of a red glow by
night. The vents should be closed with fired bricks well before the maximum temperature is attained
in order to regulate the burning rate and, thus, help to even out the temperature amongst the bricks.
The maintaining of this temperature for several hours requires a last charge of fuel, the closure of the
tunnel mouths and the sealing of closed vents with mud (ILO; 1999).
The scove should be left to cool naturally for at least three to four days. Then if necessary some
bricks may be removed from the outside to speed the later stages of cooling. Subsequently, the
bricks may be left in position until sold. Before collection or despatch, under- and over-fired bricks
must be discarded and the remainder, if of variable quality, should be sorted out into good quality,
‘seconds’ and soft-fired bricks. Rejects may be incorporated in the next scove (ILO; 1999).
Although wood is generally the fuel used in scoves, oil-burners are used in some countries. Coal,
which is also an alternative fuel for scoves, requires a special grate at each end of the tunnel mouth,
and is therefore more appropriate for firing in permanent kilns (ILO; 1999).
The fuel efficiency of scoves is low, 16000 MJ of heat being required per 1,000 bricks for a typical
African scove. A square scove has a smaller cooling area than a rectangular scove, for a given number
of bricks. However, it will require a relatively longer tunnel which may exceed the allowed length for
proper lighting of the scove. Thus, small kilns could be square while larger ones may need to be
rectangular (ILO; 1999).
In order to increase the heat efficiency, the height of a scove should be as great as possible, so long
as saleable bricks are obtained from the top. Safety must be borne in mind, however, as high scoves
tend to be unstable as a result of shrinkage of bricks during firing. Moreover, a high setting
complicates the placing of green bricks on top courses, and increases the risk of accidents (ILO;
1999).
A scove may be built for firing a few thousand bricks only, but will be less fuel efficient than larger
scoves.
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
Scotch kiln
The Scotch kiln is similar to the scove, except that the base, the fire tunnels, and the outer walls are
permanently built with bricks set in mortar. The kiln itself has no permanent top, green bricks being
set inside the kiln. Walls on either side are strengthened, and corners are massively constructed.
Access into the kiln is through a doorway in the end walls. This doorway is filled temporarily with
closely laid bricks (without mortar) during kiln operations (ILO; 1999).
Wood is often used for firing the kiln, although oil burners or coal grates may also be installed. The
sink of the bricks - after shrinkage - is more easily measured than in the clamp or scove kiln, since the
fixed position of the permanent side walls may be used as a reference point. The sink gives an
indication of the firing process within the kiln (ILO; 1999).
The advantages of the Scotch kiln over other permanent kiln structures are its simple design and easy
erection. Setting and drawing of bricks are also simple.
The Scotch kilns, like the clamp and scove, are updraught kilns. They have been widely used in
developing countries. Their chief failing is the irregular heating and consequent large proportion of
under- and over-burnt bricks. This is especially true for clays with a short vitrification range as they
cannot be fired without a good temperature control. Fuel consumption of the order of 16,000 MJ per
1,000 bricks is generally the norm for Scotch kilns (ILO; 1999).

Down-draught kiln
In the down-draught kiln, hot gases from burning fuel are deflected to the top of the kiln which must
have a permanent roof. They then flow down between the green bricks to warm and fire them. The
green bricks rest either upon an open-work support of previously fired bricks or upon a perforated
floor through which the warm gases flow. These gases are then exhausted through a chimney outside
the area of the kiln after passage through an exhaust tunnel linking the kiln floor to the chimney. The
warm gases rising through the height of the chimney provide sufficient draught to pull the hot gases
down continually through the stack of green bricks (ILO; 1999).
The down-draught kiln is more heat efficient than the up-draught kiln described earlier.
Rectangular down-draught kilns are simple to build, although they require also steel tie-bars as
reinforcement. They however have the advantage of being easier to set with green bricks than
circular kilns.
Hot gases rise to the arched crown of the kiln and are drawn down between open set bricks by the
chimney “suction”, through the perforated floor along its centre line. There should be a few small
holes at the base of the flash wall, in the underground exhaust tunnel in order to ensure the burning
113
of bricks near the bottom of the wall. A metal sheet damper is available near the bottom of the
chimney in order to vary the flow of gases and exercise control over the operation of the kiln. The
control of air flow is achieved by the use of metal doors. These should be thick enough to avoid
distortions (ILO; 1999).
Entrance to the kiln is through small arched doorways. These are bricked up temporarily during firing.
The height of downdraught kilns should not be too great, as it is difficult and time consuming to set
bricks at heights that may not be easily reached by workers. Down-draught kilns may hold from
10,000 to 100,000 bricks. Fuel consumption depends greatly upon the condition of the kiln, the
manner of setting the bricks and the control of the firing process. For example, damp foundations
absorb heat, and a badly fitting damper may waste fuel. An under-filled kiln loses as much heat as
one properly filled. An over-filled kiln prevents the passage of hot gases, and this requires a longer
burning cycle. Too much draught allows more heat to be wasted up the chimney. Given the above
varying circumstances, the energy in form of heat required by downdraught kilns varies from 12,000
to 19,000 MJ per 1,000 bricks. An exact estimate of heat consumption requires an in-depth study of
the characteristics of the kiln (ILO; 1999).
Kiln description continuous kiln

Hoffmann kiln
The Hoffmann kiln is a multi-chamber kiln where the air warmed by cooling bricks in some chambers
pre-heats the combustion air for the fire, and exhaust gases from combustion pre-heat the green
bricks. The main advantage of this kiln is its particularly low fuel consumption rate (ILO; 1999).
The original Hoffmann kiln was circular and built around a central chimney. An arched-top tunnel
surrounds the chimney at a distance of a few meters, and is connected to it by 12 flue channels
passing through the brickwork between the tunnel and the chimney. Each flue channel can be closed
off by dropping a damper. Entrance into the tunnel is through any one of 12 wickets. During
operation most of the kiln’s tunnel is full of bricks either warming, being fired or cooling (ILO; 1999).
A typical condition of the kiln is shown in figure VII.16. All but two neighboring wickets are closed.
Cold fired bricks are drawn from one part of the tunnel adjacent to one of the open wickets and dry
green bricks are set by the other wicket. Cold air flows to the warm chimney through both wickets.
This air cannot pass through the recently set bricks as they are sealed off with a paper damper across
the whole width of the annular tunnel. The air flows through the bricks which are drawn, into warm
bricks further down the kiln close to the fire. As the air flows counter-clockwise, its temperature rises
through contact with increasingly hot bricks. The air is thus pre-heated and ready for efficient
combustion in the firing zone of the kiln where fuel is fed in through closeable holes in the tunnel
114
roof. Thus, little fuel is consumed for heating the combustion air. The latter also performs the useful
task of cooling bricks for drawing, thus making kiln space available on a relatively short time. The hot
products of combustion cannot be vented straight to the chimney through the nearest flue, as the
latter is closed. Instead, the hot gases pre-heat crude bricks. Thus, less fuel is required at the firing
stage in order to get the bricks to the maximum temperature. Next, the cooled gases flow through
recently set green bricks, bringing the latter to the water smoking stage. These bricks are sufficiently
warm to exclude the forming of condensation. Subsequently, this damper is closed, the next one
(counter-clockwise) is opened, and the bricks marked “set” start the water smoking stage. The fuel
feed, and the drawing and setting operations, are also moved counter-clockwise at this stage. Once
the part of the tunnel marked “setting” has been filled with green bricks up to the next flue, a paper
damper is pasted over the bricks and the wicket (counter-clockwise) is then broken down and cooled
fired bricks are withdrawn. The paper dampers can be torn open by reaching through the fueling
points with a metal rod (ILO; 1999).
In the original Hoffmann kiln, fuel fed through the roof falls into hollow pillars formed by bricks set
for firing. Ash from the fuel causes some discoloration of the bricks. The tunnel is subdivided into 12
notional chambers which are identified by the flue positions. Each chamber is approximately 3.5 m
long and 5 m wide. The height of each chamber is restricted to about 2.5 m for easy working
conditions (ILO; 1999).
Daily rate of production from such a continuous kiln is at least 10,000 bricks (ILO; 1999).
The advantages of the original Hoffmann design include the identical chambers, the fairly short flue
channels, and low fuel consumption (2,000 MJ per 1,000 bricks).

Bull’s Trench kiln
A large fraction of the cost of construction of the Hoffmann kiln is in the building of the arch of the
long tunnel, and in the provision of a chimney, with connecting flues and dampers.
A trench is dug in a dry soil area which is not subject to flooding. It is approximately 6 m wide and 2
to 2.5 m deep. Alternatively, especially if the soil is not sufficiently dry, the trench may be dug to only
half of this depth, while excavated material is piled up on the trench side, and held out off the trench
by a brick wall starting at the bottom of the trench. The total length of the trench is approximately
120 m. It is so constructed as to constitute a continuous trench (ILO; 1999).
When in operation, the Bull’s Trench is full of bricks being warmed, fired, or cooled. Cooled bricks are
drawn and new green bricks are set, while the fire is moved progressively around the kiln. The
exhaust gases are drawn off through 16 m high moveable metal chimneys with wide bases, which fit
over the open able vent holes set in the brick and ash top of the kiln. These chimneys are guyed with
115
ropes to protect them from strong winds. Some types of chimneys require six men to move them.
This figure also shows the method of fueling whereby small shovelfuls of less than 1.5 cm size coals
are transferred from storage bins on top of the kiln, and sprinkled in amongst the hot bricks through
the removable cast-iron feed holes. Metal sheet dampers are used within the set bricks to control
draught (ILO; 1999).
The setting of the bricks within the kiln must be such as to allow sufficient air flow between the
bricks and wide enough spaces for the insertion and burning of fuel and the accumulation of ashes.
However, the whole setting must be sufficiently strong and stable to ensure safe operation of the kiln
(ILO; 1999).
The whole Bull’s Trench kiln is very large, a normal output being 28,000 bricks per day. With a narrow
trench output could be reduced to 14,000 bricks per day. It is not possible to shorten the trench as
this will affect the heat transfer efficiency. The depth of the trench cannot be reduced either without
impairing the firing behavior. The kiln would be very big to roof over, and is most suited to dry
weather conditions. The chief advantage of this type of kiln is its low initial construction costs (ILO;
1999).
Fuel consumption is much better than in intermittent kilns, 4,500 MJ being required for firing 1,000
bricks. About 70 per cent first-class bricks can be obtained, the remaining bricks being of poorer
quality (ILO; 1999).

Habla kiln
The effective tunnel length of the Hoffmann type kiln may be increased by the building of zigzagged
chambers. The resulting kilns, known as the zigzag kilns, have a faster firing schedule than the
Hoffmann kiln. However, they require a fan - and therefore electrical power - as air must travel a
longer path and a simple chimney does not provide sufficient draught for air circulation. Fans provide
a more steady draught than chimneys and can be better controlled. They allow a larger transfer of
heat to the water-smoking stage, thus saving fuel. However, it is best to avoid condensation on fan
blades and subsequent corrosion of the latter by having gases extracted at 120 °C. This is especially
important if fuel or clay contain sulfur compounds such as pyrites which are transformed into sulfuric
acid in the kiln gases (ILO; 1999).
The zigzag kiln developed by A. Habla is an arch less kiln. One additional simplifying feature of this
kiln is that the zigzagging walls are temporary structures of green bricks which may be sold after
firing. Habla kilns are of various designs: in some kilns the flues are returned from all chambers to the
central island while in others, some of the flues are returned to the outer walls (ILO; 1999).
116
The Habla kiln is rectangular, but close to a square. Habla kilns can have up to 20 chambers, every
second chambers being accessible through a wicket. Partition walls of dried green bricks, with a
thickness of only one brick length, are alternatively built out from the central island and the outer
wall. These partition walls deflect the gases from the island to the outer wall, through the wide-set
bricks between the partitions. As the temperature of any particular chamber rises, the wide-set
bricks are first heated. Then, as bricks in the partition shrink a little, draught through the partitions
increases, and the bricks in that partition as well as the wide-set ones are fired (ILO; 1999).
Large Habla kilns, producing 25,000 bricks per day, have been built in a number of countries. The
Habla kiln is economical to construct and operate. It has a larger capacity relative to its area than
other continuous kilns. This feature reduces the costs of land and construction. Furthermore, the kiln
has a long firing zone, allowing difficult clays to be fired more easily. The long-firing path assists heat
exchange between gases and bricks, thus improving fuel efficiency. Because partitions are of green
bricks, less permanent brickwork has to be heated and cooled, thus adding to fuel efficiency. The
shrinkage of bricks in the partitions and consequent leakage of hot gases shortens the distance
travelled by the latter. Thus, less power is needed to drive the fan. As a result of partition leakage,
the kiln has relatively few “dead spaces” where heat is insufficient to fire bricks properly. The
building of partitions of green bricks at the start of each operation does not increase labor costs since
the bricks are removed for sale and may thus be regarded as part of the whole setting. Another
advantage of the Habla kiln is the easy access to the structure (ILO; 1999).

Vertical Shaft Brick Kiln
The main element of the VSBK is the vertical shaft (of rectangular or square cross-section) in which
the brick firing takes place. From the ground level, the green bricks are transported up an earthen
ramp, a mechanical lift, or a belt conveyor to the top-working platform. The green bricks are loaded,
along with coal (current VSBK implementation projects in Peru show that dry and cut biomass such as
coffee husk can also be used as fuel), into the shaft from the top and the fired bricks are unloaded
from the bottom. At the bottom, a screw jack and trolley system is used for unloading bricks from the
shaft. The unloaded fired bricks come out of the kiln through the unloading tunnel at the ground
level. The kiln works as a counter-current heat exchanger, with heat transfer taking place between
the upward moving air (continuous flow) and downward moving bricks (intermittent movement). The
maximum temperature is achieved in the middle of the shaft where fire is maintained. At an interval
of 2 to 3 hours, a batch of fired bricks is unloaded at the bottom. A batch of bricks consists of four or
six layers of bricks (Brick,Heierli and Maithel; 2008).
117
Kiln comparison according to their capacity and energy consumption.
Kiln types
Capacity
MJ per 1,000 bricks
Intermittent
Bricks/firing
Clamp
10,000-100,000
7,000
Scove
10,000-100,000
16,000
Scotch
<10,000-50,000
16,000
Down-Draught
10,000-100,000
12,000-19,000
Continuous
Bricks/day
Bull’s Trench
28,000
4,500
Hoffmann
10,000
2,000
Habla
25,000
<2,000
VSBK
10,000
<2,000
Given the fact that intermittent kilns have to be heated and cooled for ever firing, which is time
consuming, only 2-3 firings can be achieved per month.
118
Appendix 2: Official Mexican Standards for air quality measurement and emission content
evaluation
Matter
Code
NOM-020-SSA1-1993
Environmental Health
NOM-021-SSA1-1993
Standards to evaluate air
NOM-022-SSA1-1993
quality as a measure of
protection of the health
NOM-023-SSA1-1993
of the population.
Methods of
Measurement
NOM-024-SSA1-1993
Regulations establishing NOM-034-SEMARNATthe
methods
of 1993
measurement
to
determine
the
contaminant
concentration.
NOM-035-SEMARNAT1993
NOM-036-SEMARNAT1993
Recent Modification
NOM-037-SEMARNAT1993
September 26, 2005
Amendment to Mexican
Official Standard NOM025-SSA1-1993,
Environmental health.
NOM-038-SEMARNAT1993
NOM-025-SSA1-1993
Source: SEMARNAT, 2009
119
Description
Criteria for evaluating the air quality
for ozone (O3).
Criteria for evaluating air quality
with respect to carbon monoxide
(CO).
Criteria for evaluating air quality
with respect to sulfur dioxide (SO2).
Criteria for evaluating the quality of
ambient air compared to nitrogen
dioxide.
Criteria for evaluating quality of
ambient air with respect to Total
suspended particles (TSP)
Established measurement methods
to determine the concentration of
carbon monoxide in air and
procedures for the calibration of
measuring equipment.
Established measurement methods to
determine the concentration of total
suspended particulates in air and the
procedure for calibration of measuring
equipment.
Established measurement methods to
determine the concentration of ozone in
ambient air and procedures for the
calibration of measuring equipment.
Established measurement methods to
determine the concentration of nitrogen
dioxide in ambient air and procedures
for the calibration of measuring
equipment.
Established measurement methods to
determine the concentration of sulfur
dioxide in ambient air and procedures
for the calibration of measuring
equipment.
Criteria to evaluate ambient air
quality regarding particulate matter.
Maximum concentration value of
particulate
matter
suspended
particulate (TSP), particles smaller
than 10 microns (PM 10) and
particles
smaller
than
2.5
micrometers (PM 2.5) in ambient air
as a protection to the health of the
population.
Appendix 3: Questionnaire
ENCUESTAS PARA LADRILLERAS
6. ¿Presta hornos?
a) Si
b) No
Si presta hornos ¿cuántos hornos presta?
NOMBRE:
I. DATOS SOBRE HORNOS
1. ¿Qué tipo de puesto tiene?
a) Trabajador de la familia
b) Ladrillero común asalariado (indirectamente
involucrado)
c) Ladrilleros temporales (contratado por el
operador de la ladrillera)
d) Ladrilleros por propia cuenta
e) Ladrilleros patrones (dueños del terreno)
f) Patrones (rento uno o más terrenos para la
producción de ladrillos o contrato trabajadores
asalariados y ellos, personalmente, supervisan
todas las labores de producción)
g) Intermediarios (comerciantes, transportistas o
revendedores)
7. ¿Cuánto cobra por prestar su horno por
quema?
8. ¿Está el horno ubicado en el mismo terreno
donde vive?
9. ¿Qué combustibles usa para las quemas?
a) Leña
b) Gas
c) Aceite
d) Llantas
e) Otros residuos ¿Cuáles?
1. ¿Es dueño de (un) horno(s)?
a) Si
b) No
2. ¿Cuántos hornos tiene?
f) Otro material ¿Cuál?
3. Edad del horno /los hornos
1. Horno:
2. Horno:
3. Horno:
4. Horno:
5: Horno:
6: Horno:
II. GASTOS DE LADRILLERA
10. Gastos por materia prima para producir
ladrillos:
a) Combustible utilizado:
Gasto por quema:
Leña
$
Gas
$
Aceite
$
Llantas
$
Otros residuos
$
Otro material
$
4. ¿Renta un(os) hornos?
a) Si
b) No
Si renta ¿cuántos hornos renta?
b) Materiales (insumos)
Tierra
Ensolvente
Arcilla
Agua
5. ¿Cuánto paga por la renta de un horno por
quema?
120
Gasto por quema:
$
$
$
$
III. LADRILLERA EXISTENTE
11. Dirección donde se ubica de la ladrillera
17. ¿Cuántas ladrillas produce en los siguientes
meses?
Enero
Febrero
12. ¿Desde cuanto existe la ladrillera?
Marzo
Abril
13. ¿Qué tipo de ladrilleras produce (nombres)?
a)
b)
c)
d)
e)
f)
Mayo
Junio
Julio
Agosto
Septiembre
IV. ANÁLISIS DE LA DEMANDA DEL PRODUCTO
LADRILLERO
Octubre
14. Número de quemas por mes
1 Quema
2 Quemas
3 Quemas
Más de 4 quemas
Noviembre
Diciembre
15. Número de ladrillos por mes
18. ¿Cuáles son los mejores meses para la
producción de ladrillas?
16. Número de ladrillos por semana
19. ¿Cuáles son los peores meses para la
producción de ladrilleras?
20. Cantidad vendida por mes
21. Cantidad vendida por semana
121
22. Cantidad de ladrillos por quemas
1 Quema
2 Quemas
3 Quemas
Más de 4 quemas
Menos de 8 hora/día
8 horas/día
Entre 8 – 10 horas/día
Entre 10 – 12 horas/ día
Más de 12 horas
¿Cuántas horas?
23. ¿Cuál es el precio de venta del ladrillo?
Nombre de ladrilla
$/ladrilla
a)
b)
c)
d)
e)
f)
29. Sueldo: ¿Cuánto ganan los trabajadores?
V. DATOS LABORALES
24. Puesto que desempeña
Por día
$
Por semana
$
Por mes
$
Por quema
$
VI. MEMBRECÍA
30. ¿Usted es miembro de la asociación de los
ladrilleros en San Luis Potosí?
a) Si
b) No
Si es miembro ¿Desde cuándo es miembro de la
asociación?
25. ¿Cuánta gente en promedio trabaja para
Usted?
26. ¿Qué desempeñan los trabajadores?
31. ¿Es miembro de alguna otra asociación (por
ejemplo política)?
a) Si
b) No
Si es miembro en otras asociaciones ¿Cuáles?
27. Sobre los trabajadores:
Empleado/Obrero
Jornalero/peón
Otro
33. Si es miembro de alguna asociación ¿Por
qué? (ventajas)
28. Horario (promedio)
Lunes
Martes
Miércoles
Jueves
Viernes
Sábado
Domingo
122
No se sabe
¿Por qué?
VII. MEJORAS APLICADOS EN LAS LADRILLERAS
34. Intenciones aplicadas para mejorar ladrillera
a) Horno
b) Combustibles
c) Quema
d) Material
e) Trabajadores
f) Reubicación
g) Cooperación con otras ladrilleras
h) Otras:
d) Material
Bien
Mal
Igual
No se sabe
¿Por qué?
35. Si se han intentado a aplicar manejos para
mejorar la ladrillera ¿Cuáles?
Si se aplicaron mejoras ¿Cómo fue el resultado?
a) Horno
Bien
Mal
Igual
No se sabe
¿Por qué?
e) Trabajadores
Bien
Mal
Igual
No se sabe
¿Por qué?
b) Combustibles
Bien
Mal
Igual
No se sabe
¿Por qué?
f) Reubicación
Bien
Mal
Igual
No se sabe
¿Por qué?
c) Quema
Bien
Mal
Igual
g) Cooperación con otras ladrilleras
Bien
Mal
Igual
123
No se sabe
¿Por qué?
36.
¿Había
intervenciones
(evaluación,
financiamiento, MK2, etc.) de parte del gobierno
en la ladrillera?
a) Si
b) No
Si contesto si ¿Cuáles?
h) Otras:
Bien
Mal
Igual
No se sabe
¿Por qué?
37.
¿Cómo
fue
el
resultado
intervenciones/apoyo del gobierno?
Bien
Mal
Igual
No se sabe
¿Por qué?
GRACIAS!
124
de
Appendix 4: Results of production costs and income
Production costs of bricksFuels
Most of the fuels are obtained illegally from the waste plant of SLP; just sawdust is bought from
carpentries; which shows that the brick producers are creating synergies with other sectors to obtain
cleaner fuels for the firing of their bricks. The average costs per fuel per firing are illustrated in Figure
1. Most is spent on other wastes (sawdust, paper etc.) and wood, followed by used oil and plastics.
The lower costs of which is spent per firing for tires (used by 56% of the interviewees) and plastics
(used by 16% of the interviewees) can be explained by the amount (Figure 1 - Amount of fuels used
per firing) used of the fuels, but it also indicates that the price for tires and fuels are beyond the price
of wood (used by 84% of the interviewees) and used oil (used by 40% of the interviewees).
Figure 1: Average expenditure (Mexican pesos) per fuel per brick production in Tercera Chica
$2.000
$1.800
$1.850
$1.600
$1.400
$1.599
$1.200
$1.207
$1.000
$800
$750
$600
$400
$525
$200
$0
Wood
Used oil
Tires
Plastics
Others
The costs for fuels depend on the number of firings per month (Figure 2). Two firings per month have
at least a double cost compared to one firing. As already mentioned just 21% of the participants
stated that they have three firings per month, the majority (38% one firing and 42% have two firings)
has not the investment opportunity to achieve three firings/month. The high maximum costs for two
firings origin in the fact that one brick maker indicated that he does not uses tires, but to a great part
wood, an expensive fuel which increases the investment costs. Nevertheless the increase of the
production does not include a linear increase of the expenditure; this could be an opportunity for an
amalgamation of the various brick producers to make common investments.
Figure 2: Expenditure (Mexican pesos) for fuels according to firings/month in Tercera Chica
125
$20.000
$18.000
$16.000
$7.950
$14.000
$12.000
$10.000
Maximum expenditure
$10.000
Average expenditure
$5.940
$8.000
$6.000
$4.653
$4.000
$2.000
$2.457
$0
$1.000
1 firing

Minimum expenditure
$5.000
$5.100
$2.400
2 firings
3 firings
Raw brick material
For the production of bricks following raw materials are needed: soil, additives (thickener), clay, and
water. The average expenditure for the materials is 2900 MXN, soil being the most expensive
material (Figure 3). Some of the brick producers do not pay for water, given that they have dug a well
on their property.
Figure 3: Average expenditure (Mexican pesos) per raw brick material per brick production in Tercera Chica
$1.800
$1.600
$1.669
$1.400
$1.200
$1.000
$800
$600
$400
$200
$417
$450
Additives
Clay
$364
$0
Soil

Water
Workforce
As earlier described the daily payment for a workforce is: average 194 MXN, the minimum is 100MXN
and the maximum is 250 MXN. Twenty percent of the brick producers indicated that they have no
fixed daily payments. The expenditure for workforce in Figure 4 has been calculated for each firing
with the factor of 4 workers (average workforce) and 5 days per firing using the minimum, average
126
and maximum wage which is paid to the workforce according to the brick producers. The results
show that the expenditure for workforce is higher than the total expenditure for fuels and material.
Figure 4: Expenditure (Mexican pesos) for workforce per firing in Tercera Chica
$40.000
$35.000
$30.000
$25.000
$20.000
$20.000
3 firings
$15.511
2 firings
$15.000
1 firing
$10.000
$8.000
$10.000
$7.756
$5.000
$4.000
$2.000
$-
$3.878
$5.000
Minimum
Average
Maximum
expenditure
expenditure (4
expenditure (4
(4workers/5 days) workers/10 days) workers/15 days)
Total expenditure per brick production
The total expenditure per brick production includes the investment costs for fuels, raw materials, and
workforce. Figure 5 shows the minimum, average and maximum total expenditure of 1-3 firings. The
workforce amounts 40-60% of the total investment costs.
Figure 5: Total expenditure per brick production
$80.000
$70.000
$60.000
$30.600
$50.000
Maximum total expenditure
$40.000
$30.000
$23.213
$20.000
$10.000
$0
Average total expenditure
$23.000
$8.480
$15.926
$6.551
$4.700
$9.500
1 firing
2 firings
$14.850
3 firings
127
Minimum total expenditure
Gross income of brick production
The monthly gross income of the brick production is the result of the produced bricks per month
related to the price of the brick. The average prices per brick type are shown in Table 1. The average
price of the cuña brick was applied to calculate the gross income, as 100% of the interviewed
specified that they produce the brick.
Table 1: Average price per brick (pesos)
Cuña
Cuadrado
Caguamo
Bovedilla
$0,88
$0,94
$1,27
$1,20
Figure 6 shows the minimum, average, and maximum gross income according to monthly firings. The
gross income shows an exponential increasing according to the firings. Remarkable is that
overlapping exists between the gross income of the maximum gross income of one firing with the
minimum gross income of two firings, and that the average and maximum gross income of two
firings just below the minimum respectively average gross income of three firings lays. This could
indicate that the brick kilns of the brick producers who implement three firings are smaller than the
kilns of the brick producers who apply two firings per month. It could be assumed that three firings in
small kilns are applied to achieve a similar number of produced bricks as does a bigger kiln with two
firings.
Figure 6: Gross income (Mexican pesos) of brick producers in Tercera Chica
$120.000
$100.000
$47.520
$80.000
Maximum gross income
$60.000
$35.200
$36.960
$40.000
$20.000
$0
Average gross income
$14.960
$25.256
$11.342
$7.040
$14.080
1 firing
2 firings
$26.400
3 firings
128
Minimum gross income
Net incomes of brick producers in Tercera Chica
The average monthly income of the interviewed brick producer is 4791 MXN (386 USD) for one firing
per month, which lays clearly above the described by FEMAP (quoted in Blackman & Bannister)
monthly profit of 100 USD a brick producer generates in Ciudad Juarez. The difference could be
explained by the fact that the date of FEMAP is older than ten years, and that the brick producers in
Ciudad Juarez employ an average of 6 workers a day for their production, while the brick producers
in Tercera Chica contract only an average of 4 workers. Also the presented data of the net income
does not consider transportation costs of fuels and raw materials. Besides 28% of the interviewees
indicated that they gain less than the determined average income of one firing, which is less than
4791 MXN and 16% even gain less than the ascertained minimum net income of 2340 MXN for one
firing. According to specifications of the affected brick producers (16%), their income is in between
1000 - 2000 MXN per month. Reasons for the deviation could be that 20% of brick producers did not
indicate the daily payment of the contracted brick workers, which are the highest investment costs.
Figure 7: Net income (Mexican pesos) of brick producers in Tercera Chica
$45.000
$40.000
$35.000
$16.920
$30.000
Maximum net income
$25.000
$20.000
Average net income
$12.200
$13.747
$15.000
$10.000
$6.480
$5.000
$4.791
$0
$2.340
1 firing
Minimum net income
$9.330
$11.550
$4.580
2 firings
3 firings
Nevertheless the average net income of 4791 MXN is consistent with the specification that the
average income amounts 5140 MXN per month. In a family with an average of 6 members this would
mean that there is almost 800 MXN (65USD) per person on a monthly basis. The investigated
maximum net incomes for two firings and the minimum, average and maximum income for three
firings are not coinciding with the specified family income of the participating brick producers. As
mentioned, the deviation could be caused by the lack of the 20% of indicated payments for
workforce or it has to do with family business (adult sons, brothers etc.) were the family splits the
income.
129
Appendix 5: Brick kiln location (GPS), conditions and photos
Capacity
Geometry
Orientation of
firing chamber
1
15.000
Rectangular
North
2
12.000
Rectangular
East
3
12.000
Rectangular
West
4
16.000
Quadratic
East
5
11.000
Quadratic
South/East
6
10.000
Quadratic
East
7
14.000
Quadratic
South
8
15.000
Quadratic
South
9
14.000
Rectangular
South
10
11.000
Rectangular
North
11
20.000
Quadratic
East
12
12.000
Quadratic
East
13
12.000
Quadratic
North
14
14.000
Rectangular
East
15
21.000
Quadratic
East/West
16
14.000
Quadratic
East
Nr.
Location
Owner
130
Firing chamber
Condition
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Above ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Above ground
level
Beneath ground
level
Above ground
level
Kiln walls are severely damaged, supporting structure is
applied
Kiln walls are severely damaged, supporting structure is
applied
Many cracks in kiln walls, kiln structure damaged
Few cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
No cracks in kiln walls, kiln structure intact
Many cracks in kiln walls, kiln structure damaged
No cracks in kiln walls, kiln structure intact
Many cracks in kiln walls, kiln structure damaged
Few cracks in kiln walls, kiln structure intact
Many cracks in kiln walls, kiln structure damaged
Many cracks in kiln walls, kiln structure damaged
Few cracks in kiln walls, kiln structure intact
Capacity
Geometry
Orientation of
firing chamber
17
20.000
Rectangular
North/East
18
20.000
Rectangular
North/East and
South/West
19
16.000
Quadratic
North/East
20
20.000
Rectangular
South/West
21
16.000
Quadratic
East
22
14.000
Rectangular
North
23
16.000
Quadratic
North
24
16.000
Rectangular
East
25
12.000
Rectangular
East
26
12.000
Rectangular
North/East
27
18.000
Quadratic
South
28
18.000
Quadratic
South
29
15.000
Rectangular
South
30
14.000
Rectangular
North/East
31
18.000
Quadratic
South
32
18.000
Quadratic
North/West
33
8.000
Rectangular
North
Nr.
Location
Owner
131
Firing chamber
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Condition
Many cracks in kiln walls, kiln structure damaged
Many cracks in kiln walls, kiln structure damaged
Few cracks in kiln walls, kiln structure intact
Kiln walls are severely damaged, supporting structure is
applied
Few cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
Kiln walls are severely damaged, supporting structure is
applied
Kiln walls are severely damaged, supporting structure is
applied
Many cracks in kiln walls, kiln structure damaged
Few cracks in kiln walls, kiln structure intact
Many cracks in kiln walls, kiln structure damaged
No cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
Many cracks in kiln walls, kiln structure damaged
Kiln walls are severely damaged, supporting structure is
applied
Many cracks in kiln walls, kiln structure damaged
Kiln walls are severely damaged, supporting structure is
applied
Capacity
Geometry
Orientation of
firing chamber
34
17.000
Quadratic
West
35
18.000
Quadratic
South
36
15.000
Quadratic
North
37
20.000
Rectangular
South/West
38
15.000
Quadratic
North/West
39
15.000
Quadratic
West and East
40
15.000
Quadratic
East
41
10.000
Quadratic
East
42
6.000
Quadratic
East
43
11.000
Quadratic
East
44
12.000
Quadratic
South/West
45
40.000
Rectangular
East and West
46
20.000
Quadratic
East
47
14.000
Quadratic
South
48
12.000
Quadratic
North
49
18.000
Quadratic
East
50
11.000
Rectangular
West
Nr.
Location
Owner
132
Firing chamber
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Above ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Condition
Few cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
Kiln walls are severely damaged, supporting structure is
applied
Few cracks in kiln walls, kiln structure intact
Kiln walls are severely damaged, supporting structure is
applied
Still under construction
Many cracks in kiln walls, kiln structure damaged
Many cracks in kiln walls, kiln structure damaged
Kiln walls are severely damaged, supporting structure is
applied
Few cracks in kiln walls, kiln structure intact
Many cracks in kiln walls, kiln structure damaged
Kiln walls are severely damaged, supporting structure is
applied
Few cracks in kiln walls, kiln structure intact
Few cracks in kiln walls, kiln structure intact
No cracks in kiln walls, kiln structure intact
Many cracks in kiln walls, kiln structure damaged
Few cracks in kiln walls, kiln structure intact
Capacity
Geometry
Orientation of
firing chamber
51
12.000
Quadratic
North/West
52
8.000
Rectangular
North/West
53
9.500
Quadratic
East
54
13.000
Quadratic
West
55
14.000
Rectangular
East
56
12.000
Quadratic
North/West
57
10.000
Rectangular
South
Nr.
Location
Owner
133
Firing chamber
Condition
Beneath ground
level
Above ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Beneath ground
level
Kiln walls are severely damaged, supporting structure is
applied
Kiln walls are severely damaged, supporting structure is
applied
Many cracks in kiln walls, kiln structure damaged
Many cracks in kiln walls, kiln structure damaged
Many cracks in kiln walls, kiln structure damaged
Many cracks in kiln walls, kiln structure damaged
No cracks in kiln walls, kiln structure intact
134
135
136
137
138
139
140
Appendix 6: Roofing design for drying area of raw bricks
Due to rainfalls many crude bricks are lost. Brick producers intend to cover drying bricks with plastic
sheeting but often either to unexpected or heavy rainfalls many crude bricks are lost. In order to
lower losses drying areas providing roofing are necessary. Above shown images demonstrate a low
cost and low tech approach to provide roofing for large areas. The construction consists of four poles
141
carrying a light-weight-two-way-curved membrane structure. In order to keep costs low wooden
telephone posts (old posts or post involved in car accidents can be pursued at low prices). The
membrane could be made out of plastic election posters sewed together (1m/1,5m in size; are
usually thrown away after elections). The shape of the membrane with two high and two low corners
stabilizes itself. The foundations for the poles could be made out off used tires filled with concrete
which are placed 60-80 cm into the ground. As an additional support of the poles ropes connecting
the top of the poles with some sort of foundation (depending on the size of the membrane tires or
old buckets filled with concrete dug in the ground).
This kind of structure could provide sufficient rain protection and still allow the drying of the bricks
by air movement. Also at the two lower corners of the membrane rain water could be collected and
used in the production process, which could become an important aspect in the future as local
authorities are currently thinking about charging brick producers for the extraction of groundwater.
142
Appendix 7: Metering pump
Price (exchange rate November 2010) of metering pump from PMT Grupo Industrial:
Kiln capacity
Electric motor
10,000 bricks
1 HP
20,000 bricks
2 HP
Gasoline motor
2 HP
3.5 HP
40,000 bricks
3 HP
Price in MXN
(with VAT)
27,038
38,288
42,690
54,962
47,313
58,566
Price in USD
(without VAT)
1,905
2,698
3,016
3,873
3,334
4,127
6 HP
HP: Horsepower
Source: http://www.pmtgi.com.mx/index.php?option=com_content&view=article&id=50&Itemid=64
143

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